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 2019 "High relative-phase precision beam duplicator for mid-infrared femtosecond pulses"Camper A, Park H, Hageman SJ, Smith G, Auguste T, Agostini P and DiMauro LF, Optics Letters., November, 2019. Vol. 44(22), pp. 5465-5468. OSA. (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: In this Letter, we use a 0 - π square-wave phase grating to shape 1350 nm and 1450 nm femtosecond pulses and create two intense lobes at the focus of a lens. We show that the relative phase between these two lobes (the 1st and -1st orders of diffraction of the grating) is controlled very simply and precisely by shifting the position of the grating in its plane. We generate high harmonic orders from the two bright lobes and record the beating between the two emissions for each harmonic order up to the 53rd harmonic order. BibTeX: @article{Camper2019, author = {Camper, Antoine and Park, Hyunwook and Hageman, Stephen J. and Smith, Greg and Auguste, Thierry and Agostini, Pierre and DiMauro, Louis F.}, title = {High relative-phase precision beam duplicator for mid-infrared femtosecond pulses}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2019}, volume = {44}, number = {22}, pages = {5465--5468}, url = {http://ol.osa.org/abstract.cfm?URI=ol-44-22-5465}, doi = {10.1364/OL.44.005465} }  "CEP-stable high-energy ytterbium-doped fiber amplifier"Natile M, Golinelli A, Lavenu L, Guichard F, Hanna M, Zaouter Y, Chiche R, Chen X, Hergott JF, Boutu W, Merdji H and Georges P, Optics Letters., August, 2019. Vol. 44(16), pp. 3909-3912. OSA. (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on the carrier-envelope phase (CEP) stabilization of a Yb-doped fiber amplifier system delivering 30 μJ pulses at 100 kHz repetition rate. A single-shot, every-shot measurement of the CEP stability based on a simple f-2f interferometer is performed, yielding a CEP standard deviation of 320 mrad rms over 1 s. Long-term stability is also assessed, with 380 mrad measured over 1 h. This level of performance is allowed by a hybrid architecture, including a passively CEP-stabilized front-end based on difference frequency generation and an active CEP stabilization loop for the fiber amplifier system, acting on a telecom-grade integrated LiNbO3 phase modulator. Together with recent demonstrations of temporal compression down to the few-cycle regime, the presented results demonstrate the relevance of the Yb-doped high repetition rate laser for attoscience. BibTeX: @article{Natile2019, author = {Natile, M. and Golinelli, A. and Lavenu, L. and Guichard, F. and Hanna, M. and Zaouter, Y. and Chiche, R. and Chen, X. and Hergott, J. F. and Boutu, W. and Merdji, H. and Georges, P.}, title = {CEP-stable high-energy ytterbium-doped fiber amplifier}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2019}, volume = {44}, number = {16}, pages = {3909--3912}, url = {http://ol.osa.org/abstract.cfm?URI=ol-44-16-3909}, doi = {10.1364/OL.44.003909} }  "Computed stereo lensless X-ray imaging" Duarte J, Cassin R, Huijts J, Iwan B, Fortuna F, Delbecq L, Chapman H, Fajardo M, Kovacev M, Boutu W and Merdji H, Nature Photonics, April, (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: Recovering the three-dimensional (3D) properties of artificial or biological systems using low X-ray doses is challenging as most techniques are based on computing hundreds of two-dimensional (2D) projections. The requirement for a low X-ray dose also prevents single-shot 3D imaging using ultrafast X-ray sources. Here we show that computed stereo vision concepts can be applied to X-rays. Stereo vision is important in the field of machine vision and robotics. We reconstruct two X-ray stereo views from coherent diffraction patterns and compute a nanoscale 3D representation of the sample from disparity maps. Similarly to brain perception, computed stereo vision algorithms use constraints. We demonstrate that phase-contrast images relax the disparity constraints, allowing occulted features to be revealed. We also show that by using nanoparticles as labels we can extend the applicability of the technique to complex samples. Computed stereo X-ray imaging will find application at X-ray free-electron lasers, synchrotrons and laser-based sources, and in industrial and medical 3D diagnosis methods. BibTeX: @article{Duarte2019, author = {Duarte, J. and Cassin, R. and Huijts, J. and Iwan, B. and Fortuna, F. and Delbecq, L. and Chapman, H. and Fajardo, M. and Kovacev, M. and Boutu, W. and Merdji, H.}, title = {Computed stereo lensless X-ray imaging}, journal = {Nature Photonics}, year = {2019}, url = {https://doi.org/10.1038/s41566-019-0419-1}, doi = {10.1038/s41566-019-0419-1} }  "All semiconductor enhanced high-harmonic generation from a single nanostructured cone" Franz D, Kaassamani S, Gauthier D, Nicolas R, Kholodtsova M, Douillard L, Gomes J-T, Lavoute L, Gaponov D, Ducros N, Février S, Biegert J, Shi L, Kovacev M, Boutu W and Merdji H, Scientific Reports., April, 2019. Vol. 9(1), pp. 5663, (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: The enhancement and control of non-linear phenomena at a nanometer scale has a wide range of applications in science and in industry. Among these phenomena, high-harmonic generation in solids is a recent focus of research to realize next generation petahertz optoelectronic devices or compact all solid state EUV sources. Here, we report on the realization of the first nanoscale high harmonic source. The strong field regime is reached by confining the electric field from a few nanojoules femtosecond laser in a single 3D semiconductor waveguide. We reveal a strong competition between enhancement of coherent harmonics and incoherent fluorescence favored by excitonic processes. However, far from the band edge, clear enhancement of the harmonic emission is reported with a robust sustainability offering a compact nanosource for applications. We illustrate the potential of our harmonic nano-device by performing a coherent diffractive imaging experiment. Ultra-compact UV/X-ray nanoprobes are foreseen to have other applications such as petahertz electronics, nano-tomography or nano-medicine. BibTeX: @article{Franz2019, author = {Franz, Dominik and Kaassamani, Shatha and Gauthier, David and Nicolas, Rana and Kholodtsova, Maria and Douillard, Ludovic and Gomes, Jean-Thomas and Lavoute, Laure and Gaponov, Dmitry and Ducros, Nicolas and Février, Sebastien and Biegert, Jens and Shi, Liping and Kovacev, Milutin and Boutu, Willem and Merdji, Hamed}, title = {All semiconductor enhanced high-harmonic generation from a single nanostructured cone}, journal = {Scientific Reports}, year = {2019}, volume = {9}, number = {1}, pages = {5663}, url = {https://doi.org/10.1038/s41598-019-41642-y}, doi = {10.1038/s41598-019-41642-y} }  "High-order harmonic generation in an active grating"Chappuis C, Bresteau D, Auguste T, Gobert O and Ruchon T , Physical Review A., Mar, 2019. Vol. 99, pp. 033806. American Physical Society, (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: We study theoretically and experimentally high-order harmonic generation (HHG) using two noncollinear driving fields focused in gases. We show that these two fields form a nonstationary blazed active grating in the generation medium. The intensity and phase structure of this grating rule the far-field properties of the emission, such as the relative amplitude of the diffraction orders. Full macroscopic calculations and experiments support this wave-based picture of the process, complementing and extending its standard "photon" picture. This insight into the HHG process allows us to envision structuration schemes to convert femtosecond lasers to attosecond pulses with increased efficiency. BibTeX: @article{PhysRevA.99.033806, author = {Chappuis, C. and Bresteau, D. and Auguste, T. and Gobert, O. and Ruchon, T.}, title = {High-order harmonic generation in an active grating}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2019}, volume = {99}, pages = {033806}, url = {https://link.aps.org/doi/10.1103/PhysRevA.99.033806}, doi = {10.1103/PhysRevA.99.033806} }  "Orbital angular momentum from semiconductor high-order harmonics" Gauthier D, Kaassamani S, Franz D, Nicolas R, Gomes J-T, Lavoute L, Gaponov D, Février S, Jargot G, Hanna M, Boutu W and Merdji H, Optics Letters., February, 2019. Vol. 44(3), pp. 546-549. OSA, (2019). [Abstract] [BibTeX] [DOI] [URL] Abstract: Light beams carrying orbital angular momentum (OAM) have led to stunning applications in various fields from quantum information to microscopy. We examine OAM from the recently observed high-harmonic generation (HHG) in semiconductor crystals. HHG from solids could be a valuable approach for integrated high-flux short-wavelength coherent light sources. First, we verify the transfer and conservation of the OAM in the strong-field regime of interaction from the generation laser to the harmonics. Secondly, we create OAM beams by etching a spiral zone structure directly at the surface of a zinc oxide crystal. Such diffractive optics act on the generated harmonics and produces focused optical vortices with sub-micrometric size. BibTeX: @article{Gauthier2019, author = {Gauthier, David and Kaassamani, Shatha and Franz, Dominik and Nicolas, Rana and Gomes, Jean-Thomas and Lavoute, Laure and Gaponov, Dmitry and Février, Sébastien and Jargot, Gaëtan and Hanna, Marc and Boutu, Willem and Merdji, Hamed}, title = {Orbital angular momentum from semiconductor high-order harmonics}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2019}, volume = {44}, number = {3}, pages = {546--549}, url = {http://ol.osa.org/abstract.cfm?URI=ol-44-3-546}, doi = {10.1364/OL.44.000546} }  2018 "Spatio-spectral metrology at focus of ultrashort lasers: a phase-retrieval approach" Borot A and Quéré F, Opt. Express., October, 2018. Vol. 26(20), pp. 26444-26461. OSA, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: The complete characterization of an ultrashort laser beam ultimately requires the determination of its spatio-temporal electric field E(x, y, t), or its spatio-spectral counterpart Ẽ(x, y, ω). We describe a new measurement technique called INSIGHT, which determines Ẽ(x, y, ω), up to an unknown spatially-homogeneous spectral phase. Combining this information with a temporal measurement at a single point of the beam then enables the determination of the spatio-temporal field E(x, y, t). This technique is based on the combination of spatially-resolved Fourier-transform spectroscopy with an alternate-projection phase-retrieval algorithm. It can be applied to any reproducible laser source with a repetition rate higher than about 0.1 Hz, relies on a very simple device, does not require any reference beam, and circumvents the difficulty associated with the manipulation of large beam diameters by working in the vicinity of the beam focus. We demonstrate INSIGHT on a 100 TW-25 fs laser, and use the measurement results to introduce new representations for the analysis of spatio-temporal/spectral couplings of ultrashort lasers. BibTeX: @article{Borot2018, author = {Borot, Antonin and Quéré, Fabien}, title = {Spatio-spectral metrology at focus of ultrashort lasers: a phase-retrieval approach}, journal = {Opt. Express}, publisher = {OSA}, year = {2018}, volume = {26}, number = {20}, pages = {26444--26461}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-26-20-26444}, doi = {10.1364/OE.26.026444} }  "Evidence of depolarization and ellipticity of high harmonics driven by ultrashort bichromatic circularly polarized fields" Barreau L, Veyrinas K, Gruson V, Weber SJ, Auguste T, Hergott J-F, Lepetit F, Carré B, Houver J-C, Dowek D and Salières P , Nature Communications., November, 2018. Vol. 9(1), pp. 4727, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: High harmonics generated by counter-rotating laser fields at the fundamental and second harmonic frequencies have raised important interest as a table-top source of circularly polarized ultrashort extreme-ultraviolet light. However, this emission has not yet been fully characterized: in particular it was assumed to be fully polarized, leading to an uncertainty on the effective harmonic ellipticity. Here we show, through simulations, that ultrashort driving fields and ultrafast medium ionization lead to a breaking of the dynamical symmetry of the interaction, and consequently to deviations from perfectly circular and fully polarized harmonics, already at the single-atom level. We perform the complete experimental characterization of the polarization state of high harmonics generated along that scheme, giving direct access to the ellipticity absolute value and sign, as well as the degree of polarization of individual harmonic orders. This study allows defining optimal generation conditions of fully circularly polarized harmonics for advanced studies of ultrafast dichroisms. BibTeX: @article{Barreau2018, author = {Barreau, Lou and Veyrinas, Kvin and Gruson, Vincent and Weber, Sbastien J. and Auguste, Thierry and Hergott, Jean-Franois and Lepetit, Fabien and Carr, Bertrand and Houver, Jean-Christophe and Dowek, Danielle and Salires, Pascal}, title = {Evidence of depolarization and ellipticity of high harmonics driven by ultrashort bichromatic circularlypolarized fields}, journal = {Nature Communications}, year = {2018}, volume = {9}, number = {1}, pages = {4727}, url = {https://doi.org/10.1038/s41467-018-07151-8}, doi = {10.1038/s41467-018-07151-8} }  "High harmonic generation as an ultrafast EUV source for circular dichroism and attosecond photoionization spectroscopies"Salieres P, High-Brightness Sources and Light-driven Interactions., Salieres P, In High-Brightness Sources and Light-driven Interactions. Strasbourg, March, 2018. , pp. EW2B.1. Optical Society of America, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: I will review our recent studies where photoionization: i) is used to measure the complete polarization state of the high harmonic source, and ii) is studied close to autoionizing resonances with attosecond resolution. BibTeX: @inproceedings{Salieres2018, author = {Salieres, Pascal}, title = {High harmonic generation as an ultrafast EUV source for circular dichroism and attosecond photoionization spectroscopies}, booktitle = {High-Brightness Sources and Light-driven Interactions}, journal = {High-Brightness Sources and Light-driven Interactions}, publisher = {Optical Society of America}, year = {2018}, pages = {EW2B.1}, url = {http://www.osapublishing.org/abstract.cfm?URI=EUVXRAY-2018-EW2B.1}, doi = {10.1364/EUVXRAY.2018.EW2B.1} }  "High photon flux XUV source driven by few cycle pulses from a bandwidth-optimized high energy Yb-doped fiber amplifier at 1.03 µm" González AI, Lavenu L, Guichard F, Zaouter Y, Georges P, Hanna M and Ruchon T, Conference on Lasers and Electro-Optics., In Conference on Lasers and Electro-Optics. San Jose, California, May, 2018. , pp. STh1N.3. Optical Society of America, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on the advantage of high harmonic generation XUV source driven by a high repetition rate few-cycle ytterbium-doped fiber-laser. We achieve a photon energy cutoff of 140 eV with photon flux of 1012 photons/s/eV. BibTeX: @inproceedings{Gonzalez2018, author = {González, Aura Inés and Lavenu, Loïc and Guichard, Florent and Zaouter, Yoann and Georges, Patrick and Hanna, Marc and Ruchon, Thierry}, title = {High photon flux XUV source driven by few cycle pulses from a bandwidth-optimized high energy Yb-doped fiber amplifier at 1.03 µm}, booktitle = {Conference on Lasers and Electro-Optics}, journal = {Conference on Lasers and Electro-Optics}, publisher = {Optical Society of America}, year = {2018}, pages = {STh1N.3}, url = {http://www.osapublishing.org/abstract.cfm?URI=CLEO_SI-2018-STh1N.3}, doi = {10.1364/CLEO_SI.2018.STh1N.3} }  "High photon flux XUV source driven by high repetition rate > 100 kHz fiber laser" González AI, Lavenu L, Guichard F, Zaouter Y, Georges P, Hanna M and Ruchon T, High-Brightness Sources and Light-driven Interactions., In High-Brightness Sources and Light-driven Interactions. Strasbourg, March, 2018. , pp. ET1B.6. Optical Society of America, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on the advantage of Yb-lasers at high repetition rate (>100kHz) to drive a XUV source based on high harmonic generation (HHG). The XUV source is based on a tight focusing configuration with high atomic density at the gas jet target. The XUV beamline has been optimized to be driven in three modalities. (1) directly with the output of an industrial Yb-laser with 350 fs pulse duration, (2) after post-compression down to 30 fs and (3) with the Yb-laser and post-compression to few cycle. We discuss how different XUV parameters can be optimized with each laser configuration. We study the improvement of the spectral width of harmonic lines respect to the pulse duration, useful for spectroscopy experiments. We present the increase of the cutoff photon energy with short pulses. We achieved up to 150 eV with a photon flux of up to 1.412 photons/s/eV by using few cycle post-compressed pulses (14 fs). BibTeX: @inproceedings{Gonzalez2018a, author = {González, Aura Inés and Lavenu, Loïc and Guichard, Florent and Zaouter, Yoann and Georges, Patrick and Hanna, Marc and Ruchon, Thierry}, title = {High photon flux XUV source driven by high repetition rate > 100 kHz fiber laser}, booktitle = {High-Brightness Sources and Light-driven Interactions}, journal = {High-Brightness Sources and Light-driven Interactions}, publisher = {Optical Society of America}, year = {2018}, pages = {ET1B.6}, url = {http://www.osapublishing.org/abstract.cfm?URI=EUVXRAY-2018-ET1B.6}, doi = {10.1364/EUVXRAY.2018.ET1B.6} }  "Time-resolved inner-shell photoelectron spectroscopy: From a bound molecule to an isolated atom"Brauße F, Goldsztejn G, Amini K, Boll R, Bari S, Bomme C, Brouard M, Burt M, de Miranda BC, Düsterer S, Erk B, Géléoc M, Geneaux R, Gentleman AS, Guillemin R, Ismail I, Johnsson P, Journel L, Kierspel T, Köckert H, Küpper J, Lablanquie P, Lahl J, Lee JWL, Mackenzie SR, Maclot S, Manschwetus B, Mereshchenko AS, Mullins T, Olshin PK, Palaudoux J, Patchkovskii S, Penent F, Piancastelli MN, Rompotis D, Ruchon T, Rudenko A, Savelyev E, Schirmel N, Techert S, Travnikova O, Trippel S, Underwood JG, Vallance C, Wiese J, Simon M, Holland DMP, Marchenko T, Rouzée A and Rolles D (2018), Phys. Rev. A., Apr, 2018. Vol. 97, pp. 043429. American Physical Society, (2018) [BibTeX] [DOI] [URL] BibTeX: @article{PhysRevA.97.043429, author = {Brauße, Felix and Goldsztejn, Gildas and Amini, Kasra and Boll, Rebecca and Bari, Sadia and Bomme, Cédric and Brouard, Mark and Burt, Michael and de Miranda, Barbara Cunha and Düsterer, Stefan and Erk, Benjamin and Géléoc, Marie and Geneaux, Romain and Gentleman, Alexander S. and Guillemin, Renaud and Ismail, Iyas and Johnsson, Per and Journel, Lo\ic and Kierspel, Thomas and Köckert, Hansjochen and Küpper, Jochen and Lablanquie, Pascal and Lahl, Jan and Lee, Jason W. L. and Mackenzie, Stuart R. and Maclot, Sylvain and Manschwetus, Bastian and Mereshchenko, Andrey S. and Mullins, Terence and Olshin, Pavel K. and Palaudoux, Jérôme and Patchkovskii, Serguei and Penent, Francis and Piancastelli, Maria Novella and Rompotis, Dimitrios and Ruchon, Thierry and Rudenko, Artem and Savelyev, Evgeny and Schirmel, Nora and Techert, Simone and Travnikova, Oksana and Trippel, Sebastian and Underwood, Jonathan G. and Vallance, Claire and Wiese, Joss and Simon, Marc and Holland, David M. P. and Marchenko, Tatiana and Rouzée, Arnaud and Rolles, Daniel}, title = {Time-resolved inner-shell photoelectron spectroscopy: From a bound molecule to an isolated atom}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2018}, volume = {97}, pages = {043429}, url = {https://link.aps.org/doi/10.1103/PhysRevA.97.043429}, doi = {10.1103/PhysRevA.97.043429} }  "Interferometric control of the ellipticity of a femtosecond extreme ultraviolet source" Gruson V, Weber SJ, Barreau L, Hergott J-F, Lepetit F, Auguste T, Carré B, Salières P and Ruchon T, Journal of the Optical Society Of America B., April, 2018. Vol. 35(4), pp. A15-A21. OSA, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: A method for ultrafast ellipticity modulation of femtosecond intense lasers is introduced and demonstrated. The method is based on the coherent superimposition of two linearly polarized visible/infrared (Vis-IR) laser beams with orthogonal polarizations. Tuning their delay by a quarter of the wavelength, i.e., a few hundred nanometers, achieves the same function as the rotation of a quarter-wave plate by 45°, switching the polarization from linear to circular. We demonstrate the portability of this method to high-intensity processes by upconverting a femtosecond Vis-IR laser beam to the extreme ultraviolet (EUV) spectral range through high-harmonic generation. These results open the way to lock-in detection of small absorption chiroptical signals in the EUV spectral range, including pump probe signals. BibTeX: @article{Gruson2018, author = {Gruson, V. and Weber, S. J. and Barreau, L. and Hergott, J.-F. and Lepetit, F. and Auguste, T. and Carré, B. and Salières, P. and Ruchon, T.}, title = {Interferometric control of the ellipticity of a femtosecond extreme ultraviolet source}, journal = {J. Opt. Soc. Am. B}, publisher = {OSA}, year = {2018}, volume = {35}, number = {4}, pages = {A15--A21}, url = {http://josab.osa.org/abstract.cfm?URI=josab-35-4-A15}, doi = {10.1364/JOSAB.35.000A15} }  "Spatio-spectral structures in high harmonic generation driven by tightly focused high repetition rate lasers"Gonzalez A-I, Jargot G, Rigaud P, Lavenu L, Guichard F, Comby A, Auguste T, Sublemontier O, Bougeard M, Zaouter Y, Georges P, Hanna M and Ruchon T, Journal of the Optical Society Of America B., April, 2018. Vol. 35(4), pp. A6-A14. OSA, 2018. [Abstract] [BibTeX] [DOI] [URL] Abstract: We investigate the spatio-spectral properties of extreme ultraviolet (XUV) high harmonic radiation driven by high repetition rate femtosecond laser systems. In the spatio-spectral domain, ring-shaped structures at each harmonic order associated with long-trajectory electrons are found to form arrow-shaped structures at the cutoff. These structures are observed with two different laser systems: an optical parametric chirped-pulse amplifier system at a central wavelength of 1.55 μm and 125 kHz repetition rate, and a temporally compressed femtosecond ytterbium fiber amplifier at 1.03 μm wavelength and 100 kHz repetition rate. As recently pointed out, the observed structures are well explained by considering the space–time atomic dipole-induced phase for short and long electron trajectories in the generation plane. The tighter focusing geometry and longer wavelength associated with these emerging driving laser systems increase the ring-like divergence and spectral broadening for high harmonics. Cutoff energies and photon fluxes obtained in argon and neon are also reported. Overall, these results shed new light on the properties of XUV radiation driven by these recently developed high average power laser systems, paving the way to high photon-flux XUV beamlines. BibTeX: @article{InesGonzalez2018, author = {Gonzalez, Aura-Inès and Jargot, Gaëtan and Rigaud, Philippe and Lavenu, Loïc and Guichard, Florent and Comby, Antoine and Auguste, Thierry and Sublemontier, Olivier and Bougeard, Michel and Zaouter, Yoann and Georges, Patrick and Hanna, Marc and Ruchon, Thierry}, title = {Spatio-spectral structures in high harmonic generation driven by tightly focused high repetition rate lasers}, journal = {J. Opt. Soc. Am. B}, publisher = {OSA}, year = {2018}, volume = {35}, number = {4}, pages = {A6--A14}, url = {http://josab.osa.org/abstract.cfm?URI=josab-35-4-A6}, doi = {10.1364/JOSAB.35.0000A6} }  "Impact of Plasmon-Induced Atoms Migration in Harmonic Generation"Shi L, Nicolas R, Andrade JRC, Boutu W, Franz D, Heidenblut T, Reinhardt C, Morgner U, Merdji H and Kovacev M , ACS Photonics., April, 2018. Vol. 5(4), pp. 1208-1214. American Chemical Society, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: Under illumination of a Ti:sapphire femtosecond oscillator, amplification of third harmonic generation by subwavelength plasmonic apertures is observed. However, the harmonic yield efficiency decays rapidly over time. In this work we investigate the physical phenomena behind the temporal attenuation of the harmonic signal. From high-resolution scanning electron micrographs and two-dimensional energy dispersive X-ray maps, we conclude that the attenuation of the third harmonic is attributed to trapping of a low-density carbon layer inside the plasmonic apertures. Furthermore, we show that the profile of the carbon deposit follows the enhanced electric near-field distribution, which indicates that the carbon atoms are transported to the field hotspot by the plasmonically enhanced optical tweezer effect. From the measurement of linear transmission spectra, we find that the dielectric constant inside the nanoholes is increased by the carbon deposit. However, numerical simulations demonstrate that the increase of dielectric constant does not reduce the electric near-field enhancement factor. Therefore, the decay of third harmonic radiation is primarily due to the strong reabsorption by the carbon deposit inside the gold-free aperture. BibTeX: @article{Shi2018, author = {Shi, Liping and Nicolas, Rana and Andrade, Jose R. C. and Boutu, Willem and Franz, Dominik and Heidenblut, Torsten and Reinhardt, Carsten and Morgner, Uwe and Merdji, Hamed and Kovacev, Milutin}, title = {Impact of Plasmon-Induced Atoms Migration in Harmonic Generation}, journal = {ACS Photonics}, publisher = {American Chemical Society}, year = {2018}, volume = {5}, number = {4}, pages = {1208--1214}, url = {https://doi.org/10.1021/acsphotonics.7b01560}, doi = {10.1021/acsphotonics.7b01560} }  "Attosecond metrology of partially coherent photoelectron wavepackets" Bourassin-Bouchet C, Barreau L, Gruson V, Quéré F, Ruchon T and Salières P (2018), High-Brightness Sources and Light-driven Interactions., In High-Brightness Sources and Light-driven Interactions. Strasbourg, March, 2018. , pp. EW3B.3. Optical Society of America. [Abstract] [BibTeX] [DOI] [URL] Abstract: We developed a novel experimental technique named Mixed-FROG for the metrology of attosecond XUV pulses. This method provides information on both the coherent and incoherent phenomena that take place during the pulse characterization. BibTeX: @inproceedings{Bourassin-Bouchet2018, author = {Bourassin-Bouchet, C. and Barreau, L. and Gruson, V. and Qur, F. and Ruchon, T. and Salires, P.}, title = {Attosecond metrology of partially coherent photoelectron wavepackets}, booktitle = {High-Brightness Sources and Light-driven Interactions}, journal = {High-Brightness Sources and Light-driven Interactions}, publisher = {Optical Society of America}, year = {2018}, pages = {EW3B.3}, url = {http://www.osapublishing.org/abstract.cfm?URI=EUVXRAY-2018-EW3B.3}, doi = {10.1364/EUVXRAY.2018.EW3B.3} }  "Time-frequency representation of autoionization dynamics in helium" Busto D, Barreau L, Isinger M, Turconi M, Alexandridi C, Harth A, Zhong S, Squibb RJ, Kroon D, Plogmaker S, Miranda M, Jiménez-Galán Á, Argenti L, Arnold CL, Feifel R, Martín F, Gisselbrecht M, L'Huillier A and Salières P, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 51(4), pp. 044002, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: Autoionization, which results from the interference between direct photoionization and photoexcitation to a discrete state decaying to the continuum by configuration interaction, is a well known example of the important role of electron correlation in light-matter interaction. Information on this process can be obtained by studying the spectral, or equivalently, temporal complex amplitude of the ionized electron wave packet. Using an energy-resolved interferometric technique, we measure the spectral amplitude and phase of autoionized wave packets emitted via the sp2+ and sp3+ resonances in helium. These measurements allow us to reconstruct the corresponding temporal profiles by Fourier transform. In addition, applying various time-frequency representations, we observe the build-up of the wave packets in the continuum, monitor the instantaneous frequencies emitted at any time and disentangle the dynamics of the direct and resonant ionization channels. BibTeX: @article{Busto2018, author = {Busto, D. and Barreau, L. and Isinger, M. and Turconi, M. and Alexandridi, C. and Harth, A. and Zhong, S. and Squibb, R. J. and Kroon, D. and Plogmaker, S. and Miranda, M. and Jiménez-Galán, Á. and Argenti, L. and Arnold, C. L. and Feifel, R. and Martín, F. and Gisselbrecht, M. and L'Huillier, A. and Salières, P.}, title = {Time-frequency representation of autoionization dynamics in helium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2018}, volume = {51}, number = {4}, pages = {044002}, url = {http://iopscience.iop.org/article/10.1088/1361-6455/aaa057/meta}, doi = {10.1088/1361-6455/aaa057} }  "Photoexcitation circular dichroism in chiral molecules" Beaulieu S, Comby A, Descamps D, Fabre B, Garcia GA, Géneaux R, Harvey AG, Légaré F, Mašín Z, Nahon L, Ordonez AF, Petit S, Pons B, Mairesse Y, Smirnova O and Blanchet V, Nature Physics., February, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: Chiral effects appear in a wide variety of natural phenomena and are of fundamental importance in science, from particle physics to metamaterials. The standard technique of chiral discrimination--photoabsorption circular dichroism--relies on the magnetic properties of a chiral medium and yields an extremely weak chiral response. Here, we propose and demonstrate an orders of magnitude more sensitive type of circular dichroism in neutral molecules: photoexcitation circular dichroism. This technique does not rely on weak magnetic effects, but takes advantage of the coherent helical motion of bound electrons excited by ultrashort circularly polarized light. It results in an ultrafast chiral response and the efficient excitation of a macroscopic chiral density in an initially isotropic ensemble of randomly oriented chiral molecules. We probe this excitation using linearly polarized laser pulses, without the aid of further chiral interactions. Our time-resolved study of vibronic chiral dynamics opens a way to the efficient initiation, control and monitoring of chiral chemical change in neutral molecules at the level of electrons. BibTeX: @article{Beaulieu2018, author = {Beaulieu, S. and Comby, A. and Descamps, D. and Fabre, B. and Garcia, G. A. and Gneaux, R. and Harvey, A. G. and Lgar, F. and Man, Z. and Nahon, L. and Ordonez, A. F. and Petit, S. and Pons, B. and Mairesse, Y. and Smirnova, O. and Blanchet, V.}, title = {Photoexcitation circular dichroism in chiral molecules}, journal = {Nature Physics}, year = {2018}, url = {https://www.nature.com/articles/s41567-017-0038-z}, doi = {10.1038/s41567-017-0038-z} }  "Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics" Williams GO, Künzel S, Daboussi S, Iwan B, Gonzalez AI, Boutu W, Hilbert V, Zastrau U, Lee HJ, Nagler B, Granados E, Galtier E, Heimann P, Barbrel B, Dovillaire G, Lee RW, Dunn J, Recoules V, Blancard C, Renaudin P, de la Varga AG, Velarde P, Audebert P, Merdji H, Zeitoun P and Fajardo M, Physical Review A., Feb, 2018. Vol. 97, pp. 023414. American Physical Society, (2018) [Abstract] [BibTeX] [DOI] [URL] Abstract: We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser is used to heat a solid, which separates the electron and ion heating time scales. The changes in absorption are measured with an independent probe pulse created through high-order-harmonic generation. We find an increase in electron temperature to have a relatively small impact on absorption, contrary to several predictions, whereas ion heating increases absorption. We compare the data to current theoretical and numerical approaches and find that a smoother electronic structure yields a better fit to the data, suggestive of a temperature-dependent electronic structure in warm dense matter. BibTeX: @article{PhysRevA.97.023414, author = {Williams, Gareth O. and Künzel, S. and Daboussi, S. and Iwan, B. and Gonzalez, A. I. and Boutu, W. and Hilbert, V. and Zastrau, U. and Lee, H. J. and Nagler, B. and Granados, E. and Galtier, E. and Heimann, P. and Barbrel, B. and Dovillaire, G. and Lee, R. W. and Dunn, J. and Recoules, V. and Blancard, C. and Renaudin, P. and de la Varga, A. G. and Velarde, P. and Audebert, P. and Merdji, H. and Zeitoun, Ph. and Fajardo, M.}, title = {Tracking the ultrafast XUV optical properties of x-ray free-electron-laser heated matter with high-order harmonics}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2018}, volume = {97}, pages = {023414}, url = {https://link.aps.org/doi/10.1103/PhysRevA.97.023414}, doi = {10.1103/PhysRevA.97.023414} }  "Resonant-Plasmon-Assisted Subwavelength Ablation by a Femtosecond Oscillator" Shi L, Iwan B, Ripault Q, Andrade JRC, Han S, Kim H, Boutu W, Franz D, Nicolas R, Heidenblut T, Reinhardt C, Bastiaens B, Nagy T, Babuskin I, Morgner U, Kim S-W, Steinmeyer G, Merdji H and Kovačev M, Phys. Rev. Applied., Feb, 2018. Vol. 9, pp. 024001. American Physical Society, (2018). [Abstract] [BibTeX] [DOI] [URL] Abstract: We experimentally demonstrate the use of subwavelength optical nanoantennas to assist a direct nanoscale ablation using the ultralow fluence of a Ti:sapphire oscillator through the excitation of surface plasmon waves. The mechanism is attributed to nonthermal transient unbonding and electrostatic ablation, which is triggered by the surface plasmon-enhanced field electron emission and acceleration in vacuum. We show that the electron-driven ablation appears for both nanoscale metallic as well as dielectric materials. While the observed surface plasmon-enhanced local ablation may limit the applications of nanostructured surfaces in extreme nonlinear nanophotonics, it, nevertheless, also provides a method for nanomachining, manipulation, and modification of nanoscale materials. Collateral thermal damage to the antenna structure can be suitably avoided, and nonlinear conversion processes can be stabilized by a dielectric overcoating of the antenna. BibTeX: @article{PhysRevApplied.9.024001, author = {Shi, Liping and Iwan, Bianca and Ripault, Quentin and Andrade, José R. C. and Han, Seunghwoi and Kim, Hyunwoong and Boutu, Willem and Franz, Dominik and Nicolas, Rana and Heidenblut, Torsten and Reinhardt, Carsten and Bastiaens, Bert and Nagy, Tamas and Babuskin, Ihar and Morgner, Uwe and Kim, Seung-Woo and Steinmeyer, Günter and Merdji, Hamed and Kovačev, Milutin}, title = {Resonant-Plasmon-Assisted Subwavelength Ablation by a Femtosecond Oscillator}, journal = {Phys. Rev. Applied}, publisher = {American Physical Society}, year = {2018}, volume = {9}, pages = {024001}, url = {https://link.aps.org/doi/10.1103/PhysRevApplied.9.024001}, doi = {10.1103/PhysRevApplied.9.024001} }  2017 "Attosecond-resolved photoionization of chiral molecules" Beaulieu S, Comby A, Clergerie A, Caillat J, Descamps D, Dudovich N, Fabre B, Géneaux R, Légaré F, Petit S, Pons B, Porat G, Ruchon T, Taïeb R, Blanchet V and Mairesse Y (2017), , Science., December, 2017. Vol. 358(6368), pp. 1288, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: Just as the atoms in a molecule can be arranged in a left- or right-handed manner, the field in a beam of light can circulate like a left- or right-handed corkscrew. Matches or mismatches in this mutual handedness give rise to an asymmetric distribution of trajectories as electrons are ejected during photoionization. Beaulieu et al. used an interferometric approach to uncover the temporal dynamics associated with this asymmetry. They probed the mirror-image isomers of camphor with circularly polarized light, which revealed the angle-dependent delays between trajectories that spanned up to 24 attoseconds.Science, this issue p. 1288Chiral light-matter interactions have been investigated for two centuries, leading to the discovery of many chiroptical processes used for discrimination of enantiomers. Whereas most chiroptical effects result from a response of bound electrons, photoionization can produce much stronger chiral signals that manifest as asymmetries in the angular distribution of the photoelectrons along the light-propagation axis. We implemented self-referenced attosecond photoelectron interferometry to measure the temporal profile of the forward and backward electron wave packets emitted upon photoionization of camphor by circularly polarized laser pulses. We measured a delay between electrons ejected forward and backward, which depends on the ejection angle and reaches 24 attoseconds. The asymmetric temporal shape of electron wave packets emitted through an autoionizing state further reveals the chiral character of strongly correlated electronic dynamics. BibTeX: @article{Beaulieu2017, author = {Beaulieu, S. and Comby, A. and Clergerie, A. and Caillat, J. and Descamps, D. and Dudovich, N. and Fabre, B. and Gneaux, R. and Lgar, F. and Petit, S. and Pons, B. and Porat, G. and Ruchon, T. and Taeb, R. and Blanchet, V. and Mairesse, Y.}, title = {Attosecond-resolved photoionization of chiral molecules}, journal = {Science}, year = {2017}, volume = {358}, number = {6368}, pages = {1288}, url = {http://science.sciencemag.org/content/358/6368/1288.abstract} }  "Laser-induced blurring of molecular structure information in high harmonic spectroscopy" Risoud F, Lévêque C, Labeye M, Caillat J, Maquet A, Salières P, Taïeb R and Shaaran T, "Laser-induced blurring of molecular structure information in high harmonic spectroscopy", Scientific Reports., December, 2017. Vol. 7(1), pp. 17302, (2017) [Abstract] [BibTeX] [DOI] [URL] Abstract: High harmonic spectroscopy gives access to molecular structure with Angström resolution. Such information is encoded in the destructive interferences occurring between the harmonic emissions from the different parts of the molecule. By solving the time-dependent Schrödinger equation, either numerically or with the molecular strong-field approximation, we show that the electron dynamics in the emission process generally results in a strong spectral smoothing of the interferences, blurring the structural information. However we identify specific generation conditions where they are unaffected. These findings have important consequences for molecular imaging and orbital tomography using high harmonic spectroscopy. BibTeX: @article{Risoud2017, author = {Risoud, François and Lévêque, Camille and Labeye, Marie and Caillat, Jérémie and Maquet, Alfred and Salières, Pascal and Taïeb, Richard and Shaaran, Tahir}, title = {Laser-induced blurring of molecular structure information in high harmonic spectroscopy}, journal = {Scientific Reports}, year = {2017}, volume = {7}, number = {1}, pages = {17302}, url = {http://www.nature.com/articles/s41598-017-17416-9}, doi = {10.1038/s41598-017-17416-9} }  "Coulomb-explosion imaging of concurrent CH2BrI photodissociation dynamics" Burt M, Boll R, Lee JWL, Amini K, Köckert H, Vallance C, Gentleman AS, Mackenzie SR, Bari S, Bomme C, Düsterer S, Erk B, Manschwetus B, Müller E, Rompotis D, Savelyev E, Schirmel N, Techert S, Treusch R, Küpper J, Trippel S, Wiese J, Stapelfeldt H, de Miranda BC, Guillemin R, Ismail I, Journel L, Marchenko T, Palaudoux J, Penent F, Piancastelli MN, Simon M, Travnikova O, Brausse F, Goldsztejn G, Rouzée A, Géléoc M, Geneaux R, Ruchon T, Underwood J, Holland DMP, Mereshchenko AS, Olshin PK, Johnsson P, Maclot S, Lahl J, Rudenko A, Ziaee F, Brouard M and Rolles D, Phys. Rev. A., Oct, 2017. Vol. 96, pp. 043415. American Physical Society, ( 2017) [Abstract] [BibTeX] [DOI] [URL] Abstract: The dynamics following laser-induced molecular photodissociation of gas-phase CH2BrI at 271.6 nm were investigated by time-resolved Coulomb-explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH2BrI undergoes C-I cleavage, depositing 65.6% of the available energy into internal product states, and that absorption of a second UV photon breaks the C-Br bond of CH2Br. Simulations confirm that this mechanism is consistent with previous data recorded at 248 nm, demonstrating the sensitivity of Coulomb-explosion imaging as a real-time probe of chemical dynamics. BibTeX: @article{PhysRevA.96.043415, author = {Burt, Michael and Boll, Rebecca and Lee, Jason W. L. and Amini, Kasra and Köckert, Hansjochen and Vallance, Claire and Gentleman, Alexander S. and Mackenzie, Stuart R. and Bari, Sadia and Bomme, Cédric and Düsterer, Stefan and Erk, Benjamin and Manschwetus, Bastian and Müller, Erland and Rompotis, Dimitrios and Savelyev, Evgeny and Schirmel, Nora and Techert, Simone and Treusch, Rolf and Küpper, Jochen and Trippel, Sebastian and Wiese, Joss and Stapelfeldt, Henrik and de Miranda, Barbara Cunha and Guillemin, Renaud and Ismail, Iyas and Journel, Lo\ic and Marchenko, Tatiana and Palaudoux, Jérôme and Penent, Francis and Piancastelli, Maria Novella and Simon, Marc and Travnikova, Oksana and Brausse, Felix and Goldsztejn, Gildas and Rouzée, Arnaud and Géléoc, Marie and Geneaux, Romain and Ruchon, Thierry and Underwood, Jonathan and Holland, David M. P. and Mereshchenko, Andrey S. and Olshin, Pavel K. and Johnsson, Per and Maclot, Sylvain and Lahl, Jan and Rudenko, Artem and Ziaee, Farzaneh and Brouard, Mark and Rolles, Daniel}, title = {Coulomb-explosion imaging of concurrent CH_2BrI photodissociation dynamics}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2017}, volume = {96}, pages = {043415}, url = {https://link.aps.org/doi/10.1103/PhysRevA.96.043415}, doi = {10.1103/PhysRevA.96.043415} }  "Investigating the origin of third harmonic generation from diabolo optical antennas" Shi L, Andrade JRC, Kim H, Han S, Nicolas R, Franz D, Boutu W, Heidenblut T, Segerink FB, Bastiaens B, Merdji H, Kim S-W, Morgner U and Kovačev M, Applied Physics Letters, October, 2017. Vol. 111(17), pp. 173102. American Institute of Physics, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: We propose to use diabolo nanoantennas for experimentally investigating the origin of the enhanced third harmonic generation by localized surface plasmon polaritons. In such a geometry, the opposing apexes of bowties are electrically connected by a thin gold nanorod, which has two important functions in discriminating the point of harmonic generation. First, the inserted gold nanorod shifts the field enhancement area to be far away from the dielectric substrate material. Next, the accumulation of free charges at the adjacent bowtie tips produces a strong electric field inside the gold nanorod. The diabolo nanoantennas allow us to examine the contribution of the bare gold susceptibility to the third harmonic conversion. Our results reveal that the bare gold does not significantly enhance the harmonic generation at high pump intensity. From this, we deduce that in regular bowtie antennas, the enhanced harmonic photons mainly arise from the substrate sapphire that is located in the feedgap of the bowtie, where the electric near-field is significantly enhanced by the localized surface plasmons. BibTeX: @article{Shi2017a, author = {Shi, Liping and Andrade, José R. C. and Kim, Hyunwoong and Han, Seunghwoi and Nicolas, Rana and Franz, Dominik and Boutu, Willem and Heidenblut, Torsten and Segerink, Frans B. and Bastiaens, Bert and Merdji, Hamed and Kim, Seung-Woo and Morgner, Uwe and Kovacev, Milutin}, title = {Investigating the origin of third harmonic generation from diabolo optical antennas}, journal = {Appl. Phys. Lett.}, publisher = {American Institute of Physics}, year = {2017}, volume = {111}, number = {17}, pages = {173102}, url = {https://doi.org/10.1063/1.5001005}, doi = {10.1063/1.5001005} }  "Tunable mid-infrared source of light carrying orbital angular momentum in the femtosecond regime" Camper A, Park H, Lai YH, Kageyama H, Li S, Talbert BK, Blaga CI, Agostini P, Ruchon T and DiMauro LF, Optics Letters., October, 2017. Vol. 42(19), pp. 3769-3772. OSA, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on a tunable intense femtosecond mid-infrared (mid-IR) light source carrying orbital angular momentum (OAM). Our setup is based on an optical parametric amplification system with an 800 nm pump shaped with a spiral phase plate. We confirm the anisotropic OAM transfer from the pump to the idler through stimulated difference frequency generation by measuring the diffraction patterns of a triangular aperture illuminated by the signal, pump, and idler beams. The tunability of the setup is demonstrated by performing measurements at 3.0 and 3.6 μm idler wavelengths. This result provides a robust method of controlling OAM in strong field physics and designing secondary sources carrying OAM in the extreme ultraviolet spectral range through high-order harmonics generation. BibTeX: @article{Camper2017, author = {Camper, Antoine and Park, Hyunwook and Lai, Yu Hang and Kageyama, Hiroyuki and Li, Sha and Talbert, Bradford K. and Blaga, Cosmin I. and Agostini, Pierre and Ruchon, Thierry and DiMauro, Louis F.}, title = {Tunable mid-infrared source of light carrying orbital angular momentum in the femtosecond regime}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2017}, volume = {42}, number = {19}, pages = {3769--3772}, url = {http://ol.osa.org/abstract.cfm?URI=ol-42-19-3769} }  "Self-optimization of plasmonic nanoantennas in strong femtosecond fields"Shi L, Iwan B, Nicolas R, Ripault Q, Andrade JRC, Han S, Kim H, Boutu W, Franz D, Heidenblut T, Reinhardt C, Bastiaens B, Nagy T, Babushkin I, Morgner U, Kim S-W, Steinmeyer G, Merdji H and Kovacev M, Optica., September, 2017. Vol. 4(9), pp. 1038-1043. OSA, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: Plasmonic dimer nanoantennas can significantly boost the electric field strength in the gap region, allowing for a modification of the feed gap geometry by femtosecond laser illumination. Using resonant bowtie antennas to enhance the electric field of a low-fluence femtosecond oscillator, here we experimentally demonstrate highly localized reshaping of the antennas, resulting in a self-optimization of the antenna shape. From high-resolution scanning electron micrographs and two-dimensional energy dispersive x-ray maps, we analyze the near-field enhanced subwavelength ablation at the nanotips and the resulting deposition of ablated materials in the feed gap. The dominant ablation mechanism is attributed to the nonthermal transient unbonding of atoms and electrostatic acceleration of ions. This process is driven by surface plasmon enhanced electron emission, with subsequent acceleration in the vacuum. This ablation is impeded in the presence of an ambient gas. A maximum of sixfold enhancement of the third-harmonic yield is observed during the reshaping process. BibTeX: @article{Shi2017, author = {Shi, Liping and Iwan, Bianca and Nicolas, Rana and Ripault, Quentin and Andrade, Jose R. C. and Han, Seunghwoi and Kim, Hyunwoong and Boutu, Willem and Franz, Dominik and Heidenblut, Torsten and Reinhardt, Carsten and Bastiaens, Bert and Nagy, Tamas and Babushkin, Ihar and Morgner, Uwe and Kim, Seung-Woo and Steinmeyer, Gnter and Merdji, Hamed and Kovacev, Milutin}, title = {Self-optimization of plasmonic nanoantennas in strong femtosecond fields}, journal = {Optica}, publisher = {OSA}, year = {2017}, volume = {4}, number = {9}, pages = {1038--1043}, url = {http://www.osapublishing.org/optica/abstract.cfm?URI=optica-4-9-1038} }  "Attosecond metrology: Optical waveform reconstruction" Salieres, P. , Nature Photonics., June, 2017. Vol. 11(6), pp. 333-335, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: The direct measurement of few-cycle optical waveforms with arbitrary polarization and weak intensity is now made possible thanks to extreme ultraviolet interferometry with isolated attosecond pulses... BibTeX: @ARTICLE{salieres2017, author = {Salieres, Pascal}, title = {Attosecond metrology: Optical waveform reconstruction}, journal = {Nat Photon}, year = {2017}, volume = {11}, pages = {333--335}, number = {6}, month = jun, abstract = {The direct measurement of few-cycle optical waveforms with arbitrary polarization and weak intensity is now made possible thanks to extreme ultraviolet interferometry with isolated attosecond pulses... }, doi = {10.1038/nphoton.2017.80}, issn = {1749-4885}, owner = {jubera}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, timestamp = {2017.06.07}, url = {http://dx.doi.org/10.1038/nphoton.2017.80} }  "Radial index of Laguerre-Gaussian modes in high-order-harmonic generation" Geneaux, R., Chappuis, C. Auguste, T., Beaulieu, S., Gorman, T., Lepetit, F., DiMauro, L. et Ruchon, T., Phys. Rev. A Vol. 8, pp. 14971- y, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: High-order-harmonic generation (HHG) is a tabletop and tunable source of extreme ultraviolet (XUV) light. Its flexibility was lately evidenced by the production of Laguerre-Gaussian (LG) modes in the XUV with a known azimuthal index. Here we investigate the role of the radial index of LG modes in HHG. We show both numerically and experimentally that the mode content of the emitted XUV radiation can be tuned by controlling the weight of the different quantum trajectories involved in the process. The appearance of high-order radial modes is finally linked to the atomic dipole phase of HHG. These results extend the capabilities of shaping the spatial mode of ultrashort XUV pulses of light. BibTeX: @ARTICLE{Genaux2017, author = {Géneaux, Romain and Chappuis, Céline and Auguste, Thierry and Beaulieu, Samuel and Gorman, Timothy T. and Lepetit, Fabien and DiMauro, Louis F. and Ruchon, Thierry..}, title = {Tunable orbital angular momentum in high-harmonic generation}, journal = {Phys. Rev. A}, year = {2017}, volume = {95}, pages = {051801--}, month = apr, abstract = {High-order-harmonic generation (HHG) is a tabletop and tunable source of extreme ultraviolet (XUV) light. Its flexibility was lately evidenced by the production of Laguerre-Gaussian (LG) modes in the XUV with a known azimuthal index. Here we investigate the role of the radial index of LG modes in HHG. We show both numerically and experimentally that the mode content of the emitted XUV radiation can be tuned by controlling the weight of the different quantum trajectories involved in the process. The appearance of high-order radial modes is finally linked to the atomic dipole phase of HHG. These results extend the capabilities of shaping the spatial mode of ultrashort XUV pulses of light.}, doi = {10.1103/PhysRevA.95.051801}, owner = {jubera}, publisher = {The Author(s)}, timestamp = {2017.05.05}, url = {https://link.aps.org/doi/10.1103/PhysRevA.95.051801} }  "Tunable orbital angular momentum in high-harmonic generation" Gauthier, D., Ribič, P.R., Adhikary, G., Camper, A., Chappuis, C., Cucini, R., DiMauro, L.F., Dovillaire, G., Frassetto, F., Géneaux, R., Miotti, P., Poletto, L., Ressel, B., Spezzani, C., Stupar, M., Ruchon, T. and De Ninno, G., Nature Communications Vol. 8, pp. 14971- y, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light-matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon's angular momentum at short-wavelengths. The methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms. BibTeX: @ARTICLE{Gauthier2017, author = {Gauthier, D. and Ribič, P. Rebernik and Adhikary, G. and Camper, A. and Chappuis, C. and Cucini, R. and DiMauro, L. F. and Dovillaire, G. and Frassetto, F. and Géneaux, R. and Miotti, P. and Poletto, L. and Ressel, B. and Spezzani, C. and Stupar, M. and Ruchon, T. and De Ninno, G.}, title = {Tunable orbital angular momentum in high-harmonic generation}, journal = {Nature Communications}, year = {2017}, volume = {8}, pages = {14971--}, month = apr, abstract = {Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light-matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon's angular momentum at short-wavelengths. The methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.}, doi = {10.1038/ncomms14971}, owner = {jubera}, publisher = {The Author(s)}, timestamp = {2017.04.06}, url = {http://dx.doi.org/10.1038/ncomms14971} }  "Phase-resolved two-dimensional spectroscopy of electronic wave packets by laser-induced XUV free induction decay" Beaulieu, S., Bloch, E., Barreau, L., Comby, A., Descamps, D., Géneaux, R., Légaré, F., Petit, S. and Mairesse, Y., Phys. Rev. A, Vol. 95, pp. 041401, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present a time- and phase-resolved, background-free scheme to study the extreme ultraviolet dipole emission of a bound electronic wave packet, without the use of any extreme ultraviolet exciting pulse. Using multiphoton transitions, we populate a superposition of quantum states which coherently emit extreme ultraviolet radiation through free induction decay. This emission is probed and controlled, both in amplitude and phase, by a time-delayed infrared femtosecond pulse. We directly measure the laser-induced dephasing of the emission by using a simple heterodyne detection scheme based on two-source interferometry. This technique provides rich information about the interplay between the laser field and the Coulombic potential on the excited electron dynamics. Its background-free nature enables us to use a large range of gas pressures and to reveal the influence of collisions in the relaxation process. BibTeX: @ARTICLE{PhysRevA.95.041401, author = {Beaulieu, S. and Bloch, E. and Barreau, L. and Comby, A. and Descamps, D. and Géneaux, R. and Légaré, F. and Petit, S. and Mairesse, Y.}, title = {Phase-resolved two-dimensional spectroscopy of electronic wave packets by laser-induced XUV free induction decay}, journal = {Phys. Rev. A}, year = {2017}, volume = {95}, pages = {041401}, month = {Apr}, abstract = {We present a time- and phase-resolved, background-free scheme to study the extreme ultraviolet dipole emission of a bound electronic wave packet, without the use of any extreme ultraviolet exciting pulse. Using multiphoton transitions, we populate a superposition of quantum states which coherently emit extreme ultraviolet radiation through free induction decay. This emission is probed and controlled, both in amplitude and phase, by a time-delayed infrared femtosecond pulse. We directly measure the laser-induced dephasing of the emission by using a simple heterodyne detection scheme based on two-source interferometry. This technique provides rich information about the interplay between the laser field and the Coulombic potential on the excited electron dynamics. Its background-free nature enables us to use a large range of gas pressures and to reveal the influence of collisions in the relaxation process.}, doi = {10.1103/PhysRevA.95.041401}, issue = {4}, numpages = {5}, owner = {jubera}, publisher = {American Physical Society}, timestamp = {2017.04.04}, url = {https://link.aps.org/doi/10.1103/PhysRevA.95.041401} }  "Precise Access to the Molecular-Frame Complex Recombination Dipole through High-Harmonic Spectroscopy" Schoun S, Camper A, Salières P, Lucchese R, Agostini P and DiMauro L, Phys. Rev. Lett., January, 2017. Vol. 118(3), pp. 033201-. American Physical Society, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on spectral intensity and group delay measurements of the highest-occupied molecular-orbital (HOMO) recombination dipole moment of N2 in the molecular-frame using high harmonic spectroscopy. We take advantage of the long-wavelength 1.3 μm driving laser to isolate the HOMO in the near threshold region, 19-67 eV. The precision of our group delay measurements reveals previously unseen angle-resolved spectral features associated with autoionizing resonances, and allows quantitative comparison with cutting-edge correlated 8-channel photoionization dipole moment calculations. BibTeX: @article{Schoun2017, author = {Schoun, S.B. and Camper, A. and Saličres, P. and Lucchese, R.R. and Agostini, P. and DiMauro, L.F.}, title = {Precise Access to the Molecular-Frame Complex Recombination Dipole through High-Harmonic Spectroscopy}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {2017}, volume = {118}, number = {3}, pages = {033201--}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.118.033201}, doi = {10.1103/PhysRevLett.118.033201} }  "Dynamic wavefront rotation in the attosecond lighthouse"Balogh E, Zhang C, Ruchon T, Hergott J-F, Quere F, Corkum P, Nam CH and Kim KT , Optica., In Optica. Vol. 4(1), pp. 48-53. OSA, (2017). [Abstract] [BibTeX] [DOI] [URL] Abstract: Attosecond pulses propagating in different directions, generated in a rotating wavefront of a driving laser field, can provide a source of multiple isolated attosecond pulses. Clear spatial separation of the attosecond pulses is attained if the divergence of the individual attosecond pulse is smaller than their angular separation, which is limited by the bandwidth of the driving laser pulse. Here we demonstrate both experimentally and numerically that an additional wavefront rotation is imposed during the propagation of the driving laser pulse in a highly ionizing medium. This dynamic wavefront rotation enables the generation of the isolated attosecond pulse even in the case when the conditions derived from a linear diffraction theory do not permit the angular separation. The described nonlinear phenomenon has its roots in the half-cycle ionization events, and may open up new ways to study strong field processes in highly ionizing media. BibTeX: @article{Balogh2017, author = {Balogh, Emeric and Zhang, Chunmei and Ruchon, Thierry and Hergott, Jean-Francois and Quere, Fabien and Corkum, Paul and Nam, Chang Hee and Kim, Kyung Taec}, title = {Dynamic wavefront rotation in the attosecond lighthouse}, booktitle = {Optica}, journal = {Optica}, publisher = {OSA}, year = {2017}, volume = {4}, number = {1}, pages = {48--53}, url = {http://www.osapublishing.org/optica/abstract.cfm?URI=optica-4-1-48}, doi = {10.1364/OPTICA.4.000048} }  2016 "Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron" Gruson V, Barreau L, Jiménez-Galan Á, Risoud F, Caillat J, Maquet A, Carré B, Lepetit F, Hergott J-F, Ruchon T, Argenti L, Taïeb R, Martín F & Salières P, Science. Vol. 354(6313), pp. 734-738, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Theorists have long pondered the underpinnings of the Fano resonance, a spectral feature that resembles adjacent rightside-up and upside-down peaks. An especially well-studied instance of this feature appears in the electronic spectrum of helium as a transient state undergoes delayed ionization. Two studies have now traced the dynamics of this state in real time. Gruson et al. used photoelectron spectroscopy to extract the amplitude and phase of the electron wave packet after inducing its interference with reference wave packets tuned into resonance at variable delays. Kaldun et al. used extreme ultraviolet absorption spectroscopy to probe the transient state while variably forcing ionization with a strong near-infrared field.Science, this issue pp. 734 and 738The dynamics of quantum systems are encoded in the amplitude and phase of wave packets. However, the rapidity of electron dynamics on the attosecond scale has precluded the complete characterization of electron wave packets in the time domain. Using spectrally resolved electron interferometry, we were able to measure the amplitude and phase of a photoelectron wave packet created through a Fano autoionizing resonance in helium. In our setup, replicas obtained by two-photon transitions interfere with reference wave packets that are formed through smooth continua, allowing the full temporal reconstruction, purely from experimental data, of the resonant wave packet released in the continuum. In turn, this resolves the buildup of the autoionizing resonance on an attosecond time scale. Our results, in excellent agreement with ab initio time-dependent calculations, raise prospects for detailed investigations of ultrafast photoemission dynamics governed by electron correlation, as well as coherent control over structured electron wave packets. BibTeX: @article{Gruson2016, author = {Gruson, V. and Barreau, L. and Jiménez-Galan, Á. and Risoud, F. and Caillat, J. and Maquet, A. and Carré, B. and Lepetit, F. and Hergott, J.-F. and Ruchon, T. and Argenti, L. and Taďeb, R. and Martín, F. and Saličres, P.}, title = {Attosecond dynamics through a Fano resonance: Monitoring the birth of a photoelectron}, journal = {Science}, year = {2016}, volume = {354}, number = {6313}, pages = {734--738}, url = {http://science.sciencemag.org/content/354/6313/734}, doi = {10.1126/science.aah5188} }  "Probing ultrafast dynamics of chiral molecules using time-resolved photoelectron circular dichroism" Beaulieu S, Comby A, Fabre B, Descamps D, Ferre A, Garcia G, Geneaux R, Legare F, Nahon L, Petit S, Ruchon T, Pons B, Blanchet V and Mairesse Y, Faraday Discuss. Vol. 194(0), pp. 325-348. The Royal Society of Chemistry, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Measuring the ultrafast dynamics of chiral molecules in the gas phase has been a long standing and challenging quest of molecular physics. The main limitation to reach that goal has been the lack of highly sensitive chiroptical measurement. By enabling chiral discrimination with up to several 10% of sensitivity, photoelectron circular dichroism (PECD) offers a solution to this issue. However, tracking ultrafast processes requires measuring PECD with ultrashort light pulses. Here we compare the PECD obtained with different light sources, from the extreme ultraviolet to the mid-infrared range, leading to different ionization regimes: single-photon, resonance-enhanced multiphoton, above-threshold and tunnel ionization. We use single and multiphoton ionization to probe the ultrafast relaxation of fenchone molecules photoexcited in their first Rydberg states. We show that time-resolved PECD enables revealing dynamics much faster than the population decay of the Rydberg states, demonstrating the high sensitivity of this technique to vibronic relaxation. BibTeX: @article{beaulieu2016bis, author = {Beaulieu, Samuel and Comby, Antoine and Fabre, Baptiste and Descamps, Dominique and Ferre, Amelie and Garcia, Gustavo and Geneaux, Romain and Legare, Francois and Nahon, Laurent and Petit, Stephane and Ruchon, Thierry and Pons, Bernard and Blanchet, Valerie and Mairesse, Yann}, title = {Probing ultrafast dynamics of chiral molecules using time-resolved photoelectron circular dichroism}, journal = {Faraday Discuss.}, publisher = {The Royal Society of Chemistry}, year = {2016}, volume = {194}, number = {0}, pages = {325--348}, url = {http://dx.doi.org/10.1039/C6FD00113K}, doi = {10.1039/C6FD00113K} }  "Molecular frame photoemission by a comb of elliptical high-order harmonics: a sensitive probe of both photodynamics and harmonic complete polarization state"Veyrinas K, Gruson V, Weber SJ, Barreau L, Ruchon T, Hergott J-F, Houver J-C, Lucchese RR, Salieres P & Dowek D, Faraday Discuss. , pp. -. The Royal Society of Chemistry, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Due to the intimate anisotropic interaction between an XUV light field and a molecule resulting in photoionization (PI), molecular frame photoelectron angular distributions (MFPADs) are most sensitive probes of both electronic/nuclear dynamics and the polarization state of the ionizing light field. Consequently, they encode the complex dipole matrix elements describing the dynamics of the PI transition, as well as the three normalized Stokes parameters s1, s2, s3 characterizing the complete polarization state of the light, operating as molecular polarimetry. The remarkable development of advanced light sources delivering attosecond XUV pulses opens the perspective to visualize the primary steps of photochemical dynamics in time-resolved studies, at the natural attosecond to few femtosecond time-scales of electron dynamics and fast nuclear motion. It is thus timely to investigate the feasibility of measurement of MFPADs when PI is induced e.g., by an attosecond pulse train (APT) corresponding to a comb of discrete high-order harmonics. In the work presented here, we report MFPAD studies based on coincident electron-ion 3D momentum imaging in the context of ultrafast molecular dynamics investigated at the PLFA facility (CEA-SLIC), with two perspectives: (i) using APTs generated in atoms/molecules as a source for MFPAD-resolved PI studies, and (ii) taking advantage of molecular polarimetry to perform a complete polarization analysis of the harmonic emission of molecules, a major challenge of high harmonic spectroscopy. Recent results illustrating both aspects are reported for APTs generated in unaligned SF6 molecules by an elliptically polarized infrared driving field. The observed fingerprints of the elliptically polarized harmonics include the first direct determination of the complete s1, s2, s3 Stokes vector, equivalent to (ψ, ε, P), the orientation and the signed ellipticity of the polarization ellipse, and the degree of polarization P. They are compared to so far incomplete results of XUV optical polarimetry. We finally discuss the comparison between the outcomes of photoionization and high harmonic spectroscopy for the description of molecular photodynamics. BibTeX: @article{Veyrinas2016, author = {Veyrinas, K. and Gruson, V. and Weber, S. J. and Barreau, L. and Ruchon, T. and Hergott, J.-F. and Houver, J.-C. and Lucchese, R. R. and Salieres, P. and Dowek, D.}, title = {Molecular frame photoemission by a comb of elliptical high-order harmonics: a sensitive probe of both photodynamics and harmonic complete polarization state}, journal = {Faraday Discuss.}, publisher = {The Royal Society of Chemistry}, year = {2016}, pages = {--}, url = {http://pubs.rsc.org/en/content/articlelanding/2016/fd/c6fd00137h#!divAbstract}, doi = {10.1039/C6FD00137H} }  "Universality of photoelectron circular dichroism in the photoionization of chiral molecules" Beaulieu S, Ferré A, Géneaux R, Canonge R, Descamps D, Fabre B, Fedorov N, Légaré F, Petit S, Ruchon T, Blanchet V, Mairesse Y et Pons B, New Journal of Physics. Vol. 18(10), pp. 102002-, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Photoionization of chiral molecules by circularly polarized radiation gives rise to a strong forward/backward asymmetry in the photoelectron angular distribution, referred to as photoelectron circular dichroism (PECD). Here we show thatÂ PECD is a universal effect that reveals the inherent chirality of the target in all ionization regimes: single photon, multiphoton, above-threshold and tunnel ionization. These different regimes provide complementary spectroscopic information at electronic and vibrational levels. The universality of the PECD can be understood in terms of a classical picture of the ionizing process, in which electron scattering on the chiral potential under the influence of a circularly polarized electric field results in a strong forward/backward asymmetry. BibTeX: @article{Beaulieu2016, author = {Beaulieu, S and Ferré, A and Géneaux, R and Canonge, R and Descamps, D and Fabre, B and Fedorov, N and Légaré, F and Petit, S and Ruchon, T and Blanchet, V and Mairesse, Y and Pons, B}, title = {Universality of photoelectron circular dichroism in the photoionization of chiral molecules}, journal = {New Journal of Physics}, year = {2016}, volume = {18}, number = {10}, pages = {102002--}, url = {http://stacks.iop.org/1367-2630/18/i=10/a=102002} }  "Origin of ellipticity of high-order harmonics generated by a two-color laser field in the cross-polarized configuration" Stremoukhov S, Andreev A, Vodungbo B, Salières P, Mahieu B and Lambert G, Phys. Rev. A., Jul, 2016. Vol. 94, pp. 013855. American Physical Society, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Recently several techniques demonstrated the production of elliptically polarized high harmonics. One of these techniques consists of the interaction in a noble gas of two-color laser beams having orthogonal linear polarizations. Here we present the theoretical explanation of such a result observed in Lambert et al. [Nat. Commun. 6, 6167 (2015)]. Numerical calculations based on the nonperturbative light-atom interaction theory reproduce well the experimental data. The degree of polarization is analyzed for different harmonic orders and found to be high. With the help of a simplified theoretical model it is shown that the degree of harmonic ellipticity depends mainly on the population of atomic state sublevels with different angular momentum projections BibTeX: @article{PhysRevA.94.013855, author = {Stremoukhov, S. and Andreev, A. and Vodungbo, B. and Saličres, P.. and Mahieu, B. and Lambert, G.}, title = {Origin of ellipticity of high-order harmonics generated by a two-color laser field in the cross-polarized configuration}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2016}, volume = {94}, pages = {013855}, url = {http://link.aps.org/doi/10.1103/PhysRevA.94.013855}, doi = {10.1103/PhysRevA.94.013855} }  "Synthesis and characterization of attosecond light vortices in the extreme ultraviolet" Geneaux R, Camper A, Auguste T, Gobert O, Caillat J, Taieb R et Ruchon T, Nature Communications, August, 2016. Vol. 7, pp. -. The Author(s), (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Infrared and visible light beams carrying orbital angular momentum (OAM) are currently thoroughly studied for their extremely broad applicative prospects, among which are quantum information, micromachining and diagnostic tools. Here we extend these prospects, presenting a comprehensive study for the synthesis and full characterization of optical vortices carrying OAM in the extreme ultraviolet (XUV) domain. We confirm the upconversion rules of a femtosecond infrared helically phased beam into its high-order harmonics, showing that each harmonic order carries the total number of OAM units absorbed in the process up to very high orders (57). This allows us to synthesize and characterize helically shaped XUV trains of attosecond pulses. To demonstrate a typical use of these new XUV light beams, we show our ability to generate and control, through photoionization, attosecond electron beams carrying OAM. These breakthroughs pave the route for the study of a series of fundamental phenomena and the development of new ultrafast diagnosis tools using either photonic or electronic vortices. BibTeX: @article{Geneaux2016, author = {Geneaux, R. and Camper, A. and Auguste, T. and Gobert, O. and Caillat, J. and Taieb, R. and Ruchon, T.}, title = {Synthesis and characterization of attosecond light vortices in the extreme ultraviolet}, journal = {Nat Commun}, publisher = {The Author(s)}, year = {2016}, volume = {7}, pages = {--}, url = {http://dx.doi.org/10.1038/ncomms12583} }  "Determination of accurate electron chiral asymmetries in fenchone and camphor in the VUV range: sensitivity to isomerism and enantiomeric purity" Nahon L, Nag L, Garcia GA, Myrgorodska I, Meierhenrich U, Beaulieu S, Wanie V, Blanchet V, Geneaux R et Powis I., Physical Chemistry Chemical Physics., Vol. 18(18), pp. 12696-12706. The Royal Society of Chemistry, (2016) [Abstract] [BibTeX] [DOI] [URL] Abstract: Photoelectron circular dichroism (PECD) manifests itself as an intense forward/backward asymmetry in the angular distribution of photoelectrons produced from randomly-oriented enantiomers by photoionization with circularly-polarized light (CPL). As a sensitive probe of both photoionization dynamics and of the chiral molecular potential, PECD attracts much interest especially with the recent performance of related experiments with visible and VUV laser sources. Here we report, by use of quasi-perfect CPL VUV synchrotron radiation and using a double imaging photoelectron/photoion coincidence (i2PEPICO) spectrometer, new and very accurate values of the corresponding asymmetries on showcase chiral isomers: camphor and fenchone. These data have additionally been normalized to the absolute enantiopurity of the sample as measured by a chromatographic technique. They can therefore be used as benchmarking data for new PECD experiments, as well as for theoretical models. In particular we found, especially for the outermost orbital of both molecules, a good agreement with CMS-X[small alpha] PECD modeling over the whole VUV range. We also report a spectacular sensitivity of PECD to isomerism for slow electrons, showing large and opposite asymmetries when comparing R-camphor to R-fenchone (respectively -10% and +16% around 10 eV). In the course of this study, we could also assess the analytical potential of PECD. Indeed, the accuracy of the data we provide are such that limited departure from perfect enantiopurity in the sample we purchased could be detected and estimated in excellent agreement with the analysis performed in parallel via a chromatographic technique, establishing a new standard of accuracy, in the +/-1% range, for enantiomeric excess measurement via PECD. The i2PEPICO technique allows correlating PECD measurements to specific parent ion masses, which would allow its application to analysis of complex mixtures. BibTeX: @article{Nahon2016, author = {Nahon, Laurent and Nag, Lipsa and Garcia, Gustavo A. and Myrgorodska, Iuliia and Meierhenrich, Uwe and Beaulieu, Samuel and Wanie, Vincent and Blanchet, Valerie and Geneaux, Romain and Powis, Ivan}, title = {Determination of accurate electron chiral asymmetries in fenchone and camphor in the VUV range: sensitivity to isomerism and enantiomeric purity}, journal = {Phys. Chem. Chem. Phys.}, publisher = {The Royal Society of Chemistry}, year = {2016}, volume = {18}, number = {18}, pages = {12696--12706}, url = {http://dx.doi.org/10.1039/C6CP01293K} }  "Attosecond lighthouses in gases: A theoretical and numerical study"Auguste T, Gobert O, Ruchon T et Quere F, Phys. Rev. A., Mar, 2016. Vol. 93, pp. 033825. American Physical Society, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present an extensive theoretical and numerical study of the attosecond lighthouse effect in gases. We study how this scheme impacts the spatiotemporal structure of the driving laser field all along the generation medium, and show that this can modify the phase matching relation governing high-harmonic generation (HHG) in gases. We then present a set of numerical simulations performed to test the robustness of the effect against variations of HHG parameters, and to identify possible solutions for relaxing the constraint on the driving laser pulse duration. We thus demonstrate that the lighthouse effect can actually be achieved with laser pulses consisting of up to ~8 optical periods available from current lasers without postcompression, for instance by using an appropriate combination of 800- and 1600-nm wavelength fields. BibTeX: @article{PhysRevA.93.033825, author = {Auguste, T. and Gobert, O. and Ruchon, T. and Quere, F.}, title = {Attosecond lighthouses in gases: A theoretical and numerical study}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2016}, volume = {93}, pages = {033825}, url = {http://link.aps.org/doi/10.1103/PhysRevA.93.033825}, doi = {10.1103/PhysRevA.93.033825} }  "Impact of noise in holography with extended references in the low signal regime"Boutu W, Gauthier D, Ge X, Cassin R, Ducousso M, Gonzalez A, Iwan B, Samaan J, Wang F, Kovačev M et Merdji H, Opt. Express., Mar, 2016. Vol. 24(6), pp. 6318-6327. OSA, (2016). [Abstract] [BibTeX] [DOI] [URL] Abstract: Signal-to-noise ratio is a key factor in lensless imaging, particularly for low diffraction signal experiments in the single shot regime. We present our recent study of the noise impact on holography with extended references. Experimental data have been measured in single shot acquisition using an intense coherent soft X-ray high harmonic source. The impact of hardware and software noise under various detection conditions is discussed. A final comparison between single shot and multi-shot regimes is given. BibTeX: @article{Boutu:16, author = {W. Boutu and D. Gauthier and X. Ge and R. Cassin and M. Ducousso and A.I. Gonzalez and B. Iwan and J. Samaan and F. Wang and M. Kovačev and H. Merdji}, title = {Impact of noise in holography with extended references in the low signal regime}, journal = {Opt. Express}, publisher = {OSA}, year = {2016}, volume = {24}, number = {6}, pages = {6318--6327}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-24-6-6318}, doi = {10.1364/OE.24.006318} }  2015 Gruson V (2015), "Polarimétrie harmonique et spectroscopie de photoionisation attoseconde" [Abstract] [BibTeX] [URL] Abstract:La physique attoseconde est un domaine en pleine expansion, intrinsèquement lié au processus de génération d’harmoniques d’ordre élevé. Cette émission, sous forme d’un train d’impulsions attosecondes ou d’une impulsion attoseconde isolée, constitue une source de lumière dans le domaine spectral extrême-UV (XUV), ultra-brève, cohérente, parfaitement synchrone du champ générateur. Deux thématiques ont été abordées. La première consiste en la caractérisation complète de l’état de polarisation des harmoniques par Polarimétrie Moléculaire en collaboration avec l’ISMO-Orsay. Cette technique est basée sur la mesure de la distribution angulaire des photoélectrons dans le référentiel moléculaire lors de l’ionisation dissociative de la molécule de NO. Nous l’appliquons à trois configurations produisant un rayonnement harmonique polarisé elliptiquement. Nous obtenons ainsi, pour la première fois, la valeur absolue de l’ellipticité harmonique, son signe, ainsi que le taux de dépolarisation.La seconde thématique est la photoionisation attoseconde résonante : nous avons étudié la photoionisation de l’hélium au voisinage de la résonance d'autoionisation 2s2p à 60.15eV, excitée par une impulsion XUV accordable et sondée par une impulsion laser IR en utilisant la technique RABBIT, qui permet la mesure de l’amplitude et de la phase spectrales de la transition résonante à deux photons. Il est ainsi possible de reconstruire dans le domaine temporel, le paquet d'ondes électronique (POE) à 2 photons. Ces mesures ont été complétées par des simulations effectuées par nos collaborateurs à UAM-Madrid et au LCPMR-Paris, qui montrent que, dans nos conditions expérimentales, ce paquet à deux photons est une image fidèle du paquet résonant à un photon. Ceci représente la première reconstruction de la dynamique temporelle d’une résonance non perturbée par le champ laser, avec une résolution attoseconde. BibTeX: @phdthesis{Gruson2015, author = {Gruson, Vincent}, title = {Polarimétrie harmonique et spectroscopie de photoionisation attoseconde}, year = {2015}, note = {Thèse de doctorat dirigée par Salières, Pascal Lasers, molécules, rayonnement atmosphérique Paris Saclay 2015}, url = {http://www.theses.fr/2015SACLS227} }  "Combined high-harmonic interferometries for vectorial spectroscopy" - Spotlight on Optics - Highlighted Articles from OSA Journals Camper A, Ferré A, Blanchet V, Burgy F, Descamps D, Petit S, Ruchon T et Mairesse Y, Opt. Lett., In Optics Letters. Vol. 40(22), pp. 5387-5390. OSA, (2015) [Abstract] [BibTeX] [DOI] [URL] Abstract: We present a new method to characterize transverse vectorial light produced by high-harmonic generation (HHG). The incoherent sum of the two components of the electric field is measured using a bi-dimensional transient grating while one of the components is simultaneously characterized using two-source interferometry. The combination of these two interferometric setups enables the amplitude and phase measurement of the two vectorial components of the extreme ultraviolet radiation. We demonstrate the potential of this technique in the case of HHG in aligned nitrogen, revealing the vectorial properties of harmonics 9-17 of a Ti:sapphire laser. BibTeX: @article{Camper2-2015, author = {Camper, Antoine and FerrĂ©, AmĂ©lie and Blanchet, ValĂ©rie and Burgy, FrĂ©dĂ©ric and Descamps, Dominique and Petit, StĂ©phane and Ruchon, Thierry and Mairesse, Yann}, title = {Combined high-harmonic interferometries for vectorial spectroscopy}, booktitle = {Optics Letters}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2015}, volume = {40}, number = {22}, pages = {5387--5390}, url = {http://ol.osa.org/abstract.cfm?URI=ol-40-22-5387}, doi = {10.1364/OL.40.005387} }  "Fourier transform holography with high harmonic spectra for attosecond imaging applications"Williams GO, Gonzalez AI, Künzel S, Li L, Lozano M, Oliva E, Iwan B, Daboussi S, Boutu W, Merdji H, Fajardo M et Zeitoun P , In Optics Letters. Vol. 40(13), pp. 3205-3208. OSA. (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: We demonstrate a method of using a Fourier holographic technique to utilize attosecond soft x-ray pulses to image nanometer-scale objects. A discrete frequency comb of laser-generated high-order harmonics, yielding a train of attosecond pulses, has been used to record spatially and spectrally resolved images. The individual wavelengths were also combined to form a single image, albeit with lower spatial resolution, demonstrating the applicability of the method to using isolated attosecond pulses with continuous bandwidths. BibTeX: @article{Williams2015, author = {Williams, Gareth O. and Gonzalez, A. I. and Künzel, S. and Li, L. and Lozano, M. and Oliva, E. and Iwan, B. and Daboussi, S. and Boutu, W. and Merdji, H. and Fajardo, M. and Zeitoun, Ph.}, title = {Fourier transform holography with high harmonic spectra for attosecond imaging applications}, booktitle = {Optics Letters}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2015}, volume = {40}, number = {13}, pages = {3205--3208}, url = {http://ol.osa.org/abstract.cfm?URI=ol-40-13-3205}, doi = {10.1364/OL.40.003205} }  "Shot-to-shot intensity and wavefront stability of high-harmonic generation"Künzel S, Williams GO, Boutu W, Galtier E, Barbrel B, Lee HJ, Nagler B, Zastrau U, Dovillaire G, Lee RW, Merdji H, Zeitoun P and Fajardo M, Applied Optics - May, 2015. Vol. 54(15), pp. 4745-4749. OSA. (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on the shot-to-shot stability of intensity and spatial phase of high-harmonic generation (HHG). The intensity stability is measured for each high-harmonic (HH) order with a spectrometer. Additionally, the spatial phase is measured with an XUV wavefront sensor for a single HH order measured in a single shot, which according to our knowledge was not reported before with a Hartmann wavefront sensor. Furthermore, we compare the single-shot measurement of the spatial phase with time-integrated measurements and we show that the XUV wavefront sensor is a useful tool to simultaneously optimize the spatial phase and intensity of HHG within the available HHG parameter range used in this study. BibTeX: @article{Kunzel2015, author = {S. Künzel and G. O. Williams and W. Boutu and E. Galtier and B. Barbrel and H. J. Lee and B. Nagler and U. Zastrau and G. Dovillaire and R. W. Lee and H. Merdji and Ph. Zeitoun and M. Fajardo}, title = {Shot-to-shot intensity and wavefront stability of high-harmonic generation}, journal = {Appl. Opt.}, publisher = {OSA}, year = {2015}, volume = {54}, number = {15}, pages = {4745--4749}, url = {http://ao.osa.org/abstract.cfm?URI=ao-54-15-4745}, doi = {10.1364/AO.54.004745} }  "Self-Probing Spectroscopy of the SF6 Molecule: A Study of the Spectral Amplitude and Phase of the High Harmonic Emission" Manschwetus B, Lin N, Rothhardt J, Guichard R, Auguste T, Camper A, Breger P, Caillat J, Géléoc M, Ruchon T, Taïeb R, Carré B and Salières P, J. Phys. Chem. A., In The Journal of Physical Chemistry A., June, 2015. Vol. 119(23), pp. 6111-6122. American Chemical Society, (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present characterizations of the attosecond pulse train produced in the high harmonic generation (HHG) from SF6 molecules irradiated by a strong pulsed laser field at 800 nm. At harmonic order 17, we observe a minimum in the amplitude of the emitted spectrum and a corresponding distortion in the phase. Our experimental results are compared to two models: a multicenter interference model focused on the effect of the structure of the SF6 molecule in HHG and a model focused on the interferences between multiple ionization channels in HHG. We find that the experimental results agree very well with the multiple ionization channels model, illustrating that HHG in molecules can be very complex and that it provides insights of the intramolecular electron dynamics during the interaction process. BibTeX: @article{, author = {Manschwetus, Bastian and Lin, Nan and Rothhardt, Jan and Guichard, Roland and Auguste, Thierry and Camper, Antoine and Breger, Pierre and Caillat, JĂ©rĂ©mie and GĂ©lĂ©oc, Marie and Ruchon, Thierry and TaĂŻeb, Richard and CarrĂ©, Bertrand and SaliĂ¨res, Pascal}, title = {Self-Probing Spectroscopy of the SF6 Molecule: A Study of the Spectral Amplitude and Phase of the High Harmonic Emission}, booktitle = {The Journal of Physical Chemistry A}, journal = {J. Phys. Chem. A}, publisher = {American Chemical Society}, year = {2015}, volume = {119}, number = {23}, pages = {6111--6122}, url = {http://dx.doi.org/10.1021/acs.jpca.5b00446}, doi = {10.1021/acs.jpca.5b00446} }  "Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times"Weber SJ, Manschwetus B, Billon M, Böttcher M, Bougeard M, Breger P, Géléoc M, Gruson V, Huetz A, Lin N, Picard YJ, Ruchon T, Salières P and Carré B, Review of Scientific Instruments. Vol. 86(3), pp. 033108 - (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using both experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented. BibTeX: @article{Weber2015, author = {Weber, S. J. and Manschwetus, B. and Billon, M. and Böttcher, M. and Bougeard, M. and Breger, P. and Géléoc, M. and Gruson, V. and Huetz, A. and Lin, N. and Picard, Y. J. and Ruchon, T. and Salières, P. and Carré, B.}, title = {Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times}, journal = {Review of Scientific Instruments}, year = {2015}, volume = {86}, number = {3}, pages = {033108}, url = {http://scitation.aip.org/content/aip/journal/rsi/86/3/10.1063/1.4914464}, doi = {10.1063/1.4914464} }  "A zero dead-time multi-particle time and position sensitive detector based on correlation between brightness and amplitude"Urbain X, Bech D, Van Roy J-P, Geleoc M, Weber SJ, Huetz A and Picard YJ, Review of Scientific Instruments. Vol. 86(2), pp. 023305 - (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: A new multi-particle time and position sensitive detector using only a set of microchannel plates, a waveform digitizer, a phosphor screen, and a CMOS camera is described. The assignment of the timing information, as taken from the microchannel plates by fast digitizing, to the positions, as recorded by the camera, is based on the COrrelation between the BRightness of the phosphor screen spots, defined as their integrated intensity and the Amplitude of the electrical signals (COBRA). Tests performed by observing the dissociation of HeH, the fragmentation of H3 into two or three fragments, and the photo-double-ionization of Xenon atoms are presented, which illustrate the performances of the COBRA detection scheme. BibTeX: @article{Urbain2015, author = {Urbain, X. and Bech, D. and Van Roy, J.-P. and Geleoc, M. and Weber, S. J. and Huetz, A. and Picard, Y. J.}, title = {A zero dead-time multi-particle time and position sensitive detector based on correlation between brightness and amplitude}, journal = {Review of Scientific Instruments}, year = {2015}, volume = {86}, number = {2}, pages = {023305}, url = {http://scitation.aip.org/content/aip/journal/rsi/86/2/10.1063/1.4908597}, doi = {10.1063/1.4908597} }  "Transverse Electromagnetic Mode Conversion for High-Harmonic Self-Probing Spectroscopy"Camper A, Ferré A, Lin N, Skantzakis E, Staedter D, English E, Manschwetus B, Burgy F, Petit S, Descamps D, Auguste T, Gobert O, Carré B, Mairesse Y and Ruchon T, Photonics. Vol. 2(1), pp. 184-199 - (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on high-order harmonic (HHG) two-source interferometry (TSI) in molecular gases. We used a 0-p phase plate to create two bright spots at the focus of a lens by converting a Gaussian laser beam into a TEM please define 01 Transverse Electromagnetic Mode. The two bright foci produce two synchronized HHG sources. One of them is used to probe on-going dynamics in the generating medium, while the other serves to heterodyne the signal. The interference of the emissions in the far-field gives access to the phase difference between the two sources. In self-probing HHG phase spectroscopy, one of the two sources is used as a reference while the other one probes some on goin dynamics in the generating medium. We first compute overlap integrals to investigate the mode conversion efficiency. We then establish a clear relation between the laser phase-front curvature and the far-field overlap of the two HHG beams. Both Fresnel diffraction calculations and an experimental lens position scan are used to reveal variations of the phase front inclination in each source. We show that this arrangement offers λ X U V / 100 precision, enabling extremely sensitive phase measurements. Finally, we use this compact setup for TSI and measure phase variations across the molecular alignment revival of nitrogen and in vibrating sulfur hexafluoride. In both gases, the phase variations change sign around the ionization threshold of the investigated molecule BibTeX: @article{Camper2015, author = {Camper, Antoine and Ferré, Amélie and Lin, Nan and Skantzakis, Emmanouil and Staedter, David and English, Elizabeth and Manschwetus, Bastian and Burgy, Frédéric and Petit, Stéphane and Descamps, Dominique and Auguste, Thierry and Gobert, Olivier and Carré, B, Bertrand andCarréères, Pascal and Mairesse, Yann and Ruchon, Thierry}, title = {Transverse Electromagnetic Mode Conversion for High-Harmonic Self-Probing Spectroscopy}, journal = {Photonics}, year = {2015}, volume = {2}, number = {1}, pages = {184--199}, url = {http://www.mdpi.com/2304-6732/2/1/184}, doi = {10.3390/photonics2010184} }  "Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation"Ferré A, Boguslavskiy AE, Dagan M, Blanchet V, Bruner BD, Burgy F, Camper A, Descamps D, Fabre B, Fedorov N, Gaudin J, Geoffroy G, Mikosch J, Patchkovskii S, Petit S, Ruchon T, Soifer H, Staedter D, Wilkinson I, Stolow A, Dudovich N and Mairesse Y , Nat Commun., January, 2015. Vol. 6, pp. -. Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved - (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20-26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected. BibTeX: @article{Ferre2-2015, author = {Ferré, A. and Boguslavskiy, A. E. and Dagan, M. and Blanchet, V. and Bruner, B. D. and Burgy, F. and Camper, A. and Descamps, D. and Fabre, B. and Fedorov, N. and Gaudin, J. and Geoffroy, G. and Mikosch, J. and Patchkovskii, S. and Petit, S. and Ruchon, T. and Soifer, H. and Staedter, D. and Wilkinson, I. and Stolow, A. and Dudovich, N. and Mairesse, Y.}, title = {Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation}, journal = {Nat Commun}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, year = {2015}, volume = {6}, pages = {--}, url = {http://dx.doi.org/10.1038/ncomms6952}, doi = {10.1038/ncomms6952} }  "A table-top ultrashort light source in the extreme ultraviolet for circular dichroism experiments"Ferré A, Handschin C, Dumergue M, Burgy F, Comby A, Descamps D, Fabre B, Garcia G, Géneaux R, Merceron L, Mével E, Nahon L, Petit S, Pons B, Staedter D, Weber S, Ruchon T, Blanchet V and Mairesse Y, Nat Photon., February, 2015. Vol. 9(2), pp. 93-98. Nature Publishing Group - (2015). [Abstract] [BibTeX] [DOI] [URL] Abstract: Circular dichroism in the extreme ultraviolet range is broadly used as a sensitive structural probe of matter, from the molecular photoionization of chiral species to the magnetic properties of solids. Extending such techniques to the dynamical regime has been a long-standing quest of solid-state physics and physical chemistry, and was only achieved very recently thanks to the development of femtosecond circular extreme ultraviolet sources. Only a few large facilities, such as femtosliced synchrotrons or free-electron lasers, are currently able to produce such pulses. Here, we propose a new compact and accessible alternative solution: resonant high-order harmonic generation of an elliptical laser pulse. We show that this process, based on a simple optical set-up, delivers bright, coherent, ultrashort, quasi-circular pulses in the extreme ultraviolet. We use this source to measure photoelectron circular dichroism on chiral molecules, opening the route to table-top time-resolved femtosecond and attosecond chiroptical experiments. BibTeX: @article{Ferre2015, author = {Ferré, A. and Handschin, C. and Dumergue, M. and Burgy, F. and Comby, A. and Descamps, D. and Fabre, B. and Garcia, G. and Géneaux, R. and Merceron, L. and Mével, E. and Nahon, L. and Petit, S. and Pons, B. and Staedter, D. and Weber, S. and Ruchon, T. and Blanchet, V. and Mairesse, Y.}, title = {A table-top ultrashort light source in the extreme ultraviolet for circular dichroism experiments}, journal = {Nat Photon}, publisher = {Nature Publishing Group}, year = {2015}, volume = {9}, number = {2}, pages = {93--98}, url = {http://dx.doi.org/10.1038/nphoton.2014.314}, doi = {10.1038/nphoton.2014.314} }  2014 "Control and identification of strong field dissociative channels in CO via molecular alignment"Oppermann M, Weber SJ, Morales F, Richter M, Patchkovskii S, Csehi A, Vibok A, Ivanov M, Smirnova O and Marangos JP, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 47(12), pp. 124025 - (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: The dissociative excitation of CO was studied in the molecular frame as a function of probe laser intensity, ellipticity and polarization with respect to the molecular bond at laser wavelengths of 800 nm and 1350 nm. This allowed the identification of the main excitation pathway consisting of tunnel ionization from HOMO-2 followed by a parallel dipole transition from the second excited state B to the predissociating, third excited state C. Recollision excitation was shown to play a negligible role. Using laser induced impulsive alignment, the strong field induced coupling at 800 nm and 1350 nm of the ionic states B and C could thus be controlled by the laser polarization. This leads to a suppression of the fragmentation yield of up to 70% when the laser polarization was perpendicular to the molecular axis compared to parallel polarization. We have performed simulations of various ionization channels of CO2-. Our simulations reflect the experimental findings and show that dissociation of CO is induced by tunnelling from deeper molecular orbitals HOMO-1, HOMO-2, HOMO-3, followed by laser driven hole dynamics in the ion. BibTeX: @article{Oppermann2014, author = {Oppermann, M and Weber, S J and Morales, F and Richter, M and Patchkovskii, S and Csehi, A and Vibok, A and Ivanov, M and Smirnova, O and Marangos, J P}, title = {Control and identification of strong field dissociative channels in CO$_2^+$ via molecular alignment}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2014}, volume = {47}, number = {12}, pages = {124025--}, url = {http://stacks.iop.org/0953-4075/47/i=12/a=124025}, doi = {10.1088/0953-4075/47/12/124025} }  "High-harmonic phase spectroscopy using a binary diffractive optical element"Camper A, Ruchon T, Gauthier D, Gobert O, Salières P, Carré B and Auguste T, Phys. Rev. A., April, 2014. Vol. 89(4), pp. 043843-. American Physical Society - (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on high-order harmonic generation (HHG) using a Ti:sapphire laser beam phase shaped with a binary diffractive optical element (DOE) to create two spatially separated synchronized HHG sources at the focus of a lens. Using full three-dimensional computations, we show numerically that the harmonic dipole phase is imprinted in the resulting far-field fringe pattern. Using the corresponding experimental arrangement, we measure HHG phase in aligned carbon dioxide. This arrangement is robust, extremely stable, simple to use, and gives highly resolved fringes. It thus opens new perspectives for combined and refined HHG phase measurements in excited samples. BibTeX: @article{Camper2014, author = {Camper, A. and Ruchon, T. and Gauthier, D. and Gobert, O. and Salières, P. and Carré, B. and Auguste, T.}, title = {High-harmonic phase spectroscopy using a binary diffractive optical element}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2014}, volume = {89}, number = {4}, pages = {043843--}, url = {http://link.aps.org/doi/10.1103/PhysRevA.89.043843}, doi = {10.1103/PhysRevA.89.043843} }  "Electron trajectory control of odd and even order harmonics in high harmonic generation using an orthogonally polarised second harmonic field" Hutchison C, Houver S, Lin N, Hoffmann D, McGrath F, Siegel T, Austin D, Zaïr A, Salières P and Marangos J, Journal of Modern Optics., In Journal of Modern Optics., April, 2014. Vol. 61(7), pp. 608-614. Taylor & Francis, (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: We investigate quantum trajectory control in high-order harmonic generation using an additional orthogonally polarised second harmonic field. By controlling the relative phase between this field and the fundamental, we are able to suppress and enhance particular electron trajectories which results in a modulation of the harmonic emission. We observe a phase shift of the modulation between the short and long trajectories that is different for adjacent odd and even harmonics. These results show qualitative agreement with a full propagation calculation where the single atom response was obtained from the strong field approximation and the main results are explained by consideration of a single atom quantum orbit picture.We investigate quantum trajectory control in high-order harmonic generation using an additional orthogonally polarised second harmonic field. By controlling the relative phase between this field and the fundamental, we are able to suppress and enhance particular electron trajectories which results in a modulation of the harmonic emission. We observe a phase shift of the modulation between the short and long trajectories that is different for adjacent odd and even harmonics. These results show qualitative agreement with a full propagation calculation where the single atom response was obtained from the strong field approximation and the main results are explained by consideration of a single atom quantum orbit picture. BibTeX: @article{, author = {Hutchison, C. and Houver, S. and Lin, N. and Hoffmann, D.J. and McGrath, F. and Siegel, T. and Austin, D.R. and ZaĂŻr, A. and SaliĂ¨res, P. and Marangos, J.P.}, title = {Electron trajectory control of odd and even order harmonics in high harmonic generation using an orthogonally polarised second harmonic field}, booktitle = {Journal of Modern Optics}, journal = {Journal of Modern Optics}, publisher = {Taylor & Francis}, year = {2014}, volume = {61}, number = {7}, pages = {608--614}, url = {http://dx.doi.org/10.1080/09500340.2014.901431}, doi = {10.1080/09500340.2014.901431} }  "Single-shot studies of a Co/Pd thin film's magnetic nano-domain structure using ultrafast x-ray scattering"Ducousso M, Ge X, Boutu W, Gauthier D, Barbrel B, Wang F, Borta A, Gonzalez A-I, Billon M, Vodungbo B, Gautier J, Hawaldar R, Tudu B, Delaunay R, Tortarolo M, Zeitoun P, Luening J and Merdji H, LASER PHYSICS. TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND, FEB, 2014. Vol. 24({2}) IOP PUBLISHING LTD - (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: Understanding ultrafast dynamics of nanoscale objects is an important challenge in nanoscience and technology. Their investigation relies on the availability of ultrafast probe techniques capable of combining femtosecond time resolution with nanometer spatial resolution. Such experiments benefit greatly from the recent advent of x-ray free electron laser facilities. The extreme intensity of their short femtosecond x-ray pulses enables ultrafast snapshot characterization with nanoscale spatial resolution. Here, we demonstrate that such experiments are not uniquely limited to large-scale facilities, but that they can also be realized using high harmonics from a table-top femtosecond laser system. To do so, we have employed resonant magnetic x-ray scattering of a single 20 fs short XUV laser-harmonic pulse to characterize the nanometer sized magnetic domain structure of Co/Pd thin film. Moreover, the technique being element specific, we have looked at the domain structure within each of the two layer types by selecting harmonics resonant with the Co M-3 (60 eV) and the Pd N-3 (51 eV) edge, respectively. BibTeX: @article{Ducousso2014, author = {Ducousso, M. and Ge, X. and Boutu, W. and Gauthier, D. and Barbrel, B. and Wang, F. and Borta, A. and Gonzalez, A-I and Billon, M. and Vodungbo, B. and Gautier, J. and Hawaldar, R. and Tudu, B. and Delaunay, R. and Tortarolo, M. and Zeitoun, P. and Luening, J. and Merdji, H.}, title = {Single-shot studies of a Co/Pd thin film's magnetic nano-domain structure using ultrafast x-ray scattering}, journal = {LASER PHYSICS}, publisher = {IOP PUBLISHING LTD}, year = {2014}, volume = {24}, number = {2}, url = {http://apps.webofknowledge.com/full_record.do?product=WOS&search_mode=GeneralSearch&qid=4&SID=S2moz4yDiJiWnQm5AkK&page=1&doc=1}, doi = {10.1088/1054-660X/24/2/025301} }  "Attosecond evolution of energy- and angle-resolved photoemission spectra in two-color (XUV $+$ IR) ionization of rare gases"Picard YJ, Manschwetus B, Géléoc M, Böttcher M, Casagrande EMS, Lin N, Ruchon T, Carré B, Hergott J-F, Lepetit F, Taieb R, Maquet A and Huetz A, Phys. Rev. A., Vol. 89, pp. 031401. American Physical Society - Mars, (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: We have analyzed the angular distributions of the photoelectrons emitted upon photoionization of rare gases by a comb of harmonics in the extreme ultraviolet range, in the presence of a “dressing” infrared (IR) field with controlled delay τ, stabilized down to about ±60 as. The measurements have been performed with the help of the coincidence momentum imaging technique. We evidence marked differences in the measured angular distributions of the photoelectrons, depending on the number of IR photons exchanged. Joined to a theoretical interpretation, these observations bring new insights into the dynamics of this class of two-color photoionization processes that are a key step towards studying photoionization in the time domain, with attosecond time resolution. BibTeX: @article{Picard2014, author = {Picard, Y. J. and Manschwetus, B. and Géléoc, M. and Böttcher, M. and Casagrande, E. M. Staicu and Lin, N. and Ruchon, T. and Carré, B. and Hergott, J.-F. and Lepetit, F. and Taieb, R. and Maquet, A. and Huetz, A.}, title = {Attosecond evolution of energy- and angle-resolved photoemission spectra in two-color (XUV $+$ IR) ionization of rare gases}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2014}, volume = {89}, pages = {031401}, url = {http://link.aps.org/doi/10.1103/PhysRevA.89.031401}, doi = {10.1103/PhysRevA.89.031401} }  "Theoretical and experimental studies of broadband phase-controlled attosecond mirrors" Diveki Z, Bourassin-Bouchet C, de Rossi S, English E, Meltchakov E, Gobert O, Guénot D, Carré B, Salières P, Ruchon T and Delmotte F, Journal of Modern Optics.,In Journal of Modern Optics., January, 2014. Vol. 61(2), pp. 122-131. Taylor & Francis, (2014). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present procedures to develop and characterise chirped multilayer mirrors for attosecond pulses. The design procedure involves a simulated annealing optimisation algorithm to obtain a multilayer structure with the desired performances. The characterisation step requires the use of well-calibrated attosecond and synchrotron beam lines, allowing one to measure the amplitude and phase response of the mirror. We illustrate these approaches with a set of mirrors designed to have zero or negative dispersion. The remarkable agreement between theoretical and experimental performances validates this overall process, and demonstrates the capability of such mirrors to control the temporal profile of attosecond pulses. These tools and techniques for developing attosecond chirped mirrors will facilitate the generalisation of such components on attosecond experiments.We present procedures to develop and characterise chirped multilayer mirrors for attosecond pulses. The design procedure involves a simulated annealing optimisation algorithm to obtain a multilayer structure with the desired performances. The characterisation step requires the use of well-calibrated attosecond and synchrotron beam lines, allowing one to measure the amplitude and phase response of the mirror. We illustrate these approaches with a set of mirrors designed to have zero or negative dispersion. The remarkable agreement between theoretical and experimental performances validates this overall process, and demonstrates the capability of such mirrors to control the temporal profile of attosecond pulses. These tools and techniques for developing attosecond chirped mirrors will facilitate the generalisation of such components on attosecond experiments. BibTeX: @article{, author = {Diveki, Z. and Bourassin-Bouchet, C. and de Rossi, S. and English, E. and Meltchakov, E. and Gobert, O. and GuĂ©not, D. and CarrĂ©, B. and SaliĂ¨res, P. and Ruchon, T. and Delmotte, F.}, title = {Theoretical and experimental studies of broadband phase-controlled attosecond mirrors}, booktitle = {Journal of Modern Optics}, journal = {Journal of Modern Optics}, publisher = {Taylor & Francis}, year = {2014}, volume = {61}, number = {2}, pages = {122--131}, url = {http://dx.doi.org/10.1080/09500340.2013.869016}, doi = {10.1080/09500340.2013.869016} }  2013 "Multichannel contributions in the nonsequential double ionization of CO2"Oppermann M, Weber SJ, Frasinski LJ, Ivanov MY and Marangos JP, Phys. Rev. A., Vol. 88(4), pp. 043432-. American Physical Society - October, (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: The intermediate molecular states in the double ionization of molecules by laser-driven electron recollision are encoded into the angular-dependent signature of the process. We identify through this signature the specific ionic states participating in the double-ionization mechanism. Using CO2 as an example we employ a 1350-nm strong field at 2×1014 W cm-2 to ensure that nonsequential double ionization (NSDI) is the exclusive mechanism in CO+22 formation. Under these conditions we obtain two main results. First, the shape of the recolliding electron wave packet is inferred from measurements of the ellipticity dependence of the signal, and second, the inelastic recollision cross section in the molecular frame is extracted from the variation of the signal as a function of the angle between strong-field probe polarization and molecular axis. These results provide an angularly resolved electron-ion collision measurement in CO2 and demonstrate contributions to NSDI from both ground and first excited ionic states. BibTeX: @article{Oppermann2013, author = {Oppermann, M. and Weber, S. J. and Frasinski, L. J. and Ivanov, M. Yu. and Marangos, J. P.}, title = {Multichannel contributions in the nonsequential double ionization of CO${}_{2}$}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2013}, volume = {88}, number = {4}, pages = {043432--}, url = {http://link.aps.org/doi/10.1103/PhysRevA.88.043432}, doi = {10.1103/PhysRevA.88.043432} }  "Electron elastic back-scattering from aligned CO molecular ions in the 15–30 eV energy range "Cornaggia C, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 46(19), pp. 191001 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: Angular distributions of electrons elastically back-scattered from alignedCO ions are extracted in the 15-30 eV energy range from electron spectra recorded in field-free-aligned CO2 molecules using a femtosecond pump-probe scheme. The angular distributions are found to exhibit a steeper increase as the scattering angle goes from 150° to 180° for molecular ions aligned with the incident electron momentum. BibTeX: @article{Cornaggia2013, author = {Cornaggia, C}, title = {Electron elastic back-scattering from aligned CO+2 molecular ions in the 15-30 eV energy range}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2013}, volume = {46}, number = {19}, pages = {191001--}, url = {http://stacks.iop.org/0953-4075/46/i=19/a=191001}, doi = {10.1088/0953-4075/46/19/191001} }  "Sub-100 nanometer lensless probing of Co/Pd magnetic nanodomains using a table-top femtosecond soft X-ray harmonic source"Ge X, Ducousso M, Boutu W, Tudu B, Barbrel B, Gauthier D, Borta A, Gonzalez A-I, Wang F, Iwan B, Billon M, Perdrix M, Guillaumet D, Lepetit F, Vodungbo B, Gautier J, Hawaldar R, Tortarolo M, Delaunay R, Zeitoun P, Lüning J and Merdji H, J MOD OPTIC. Vol. Accepted - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present recent developments of our table-top femtosecond high flux harmonic beamline towards single-shot probing of magnetic nanostructures. High harmonic generation (HHG) optimization in a single and two-color infrared laser pulse mode was investigated at high laser energy. Up to 109 photons per harmonic are generated between 40 and 80 eV in a single femtosecond laser shot. These soft X-ray harmonic photons are employed to characterize at the nanoscale the magnetic network of Co/Pd multilayer samples using resonant small-angle X-ray scattering. Selecting harmonics in the vicinity of magnetically dichroic absorption resonances of cobalt and palladium (Co M2,3 at 60 eV and Pd N2,3 at 51 eV) gives access to the magnetic nanodomain spatial structure. The magnetic scattering efficiency at the Pd edge is found to be comparable to that at the Co edge. This indicates that the Pd layers exhibit a significant induced magnetic moment. Magnetic sample optimization is then performed by characterizing its scattering efficiency as a function of layer composition and number of repetitions. We finally measure the spatial organization of magnetic nanodomains with a sub-100 nm spatial resolution from a single femtosecond X-ray pulse. BibTeX: @article{GEJMO2013, author = {X. Ge and M. Ducousso and W. Boutu and B. Tudu and B. Barbrel and D. Gauthier and A. Borta and A.-I. Gonzalez and F. Wang and B. Iwan and M. Billon and M. Perdrix and D. Guillaumet and F. Lepetit and B. Vodungbo and J. Gautier and R. Hawaldar and M. Tortarolo and R. Delaunay and P. Zeitoun and J. Lüning and and H. Merdji}, title = {Sub-100 nanometer lensless probing of Co/Pd magnetic nanodomains using a table-top femtosecond soft X-ray harmonic source}, journal = {J MOD OPTIC}, year = {2013}, volume = {Accepted}, url = {http://www.tandfonline.com/doi/abs/10.1080/09500340.2013.839058#.U0PqUE8U-70}, doi = {10.1080/09500340.2013.839058} }  "Microfocusing of the FERMI@Elettra FEL beam with a K-B active optics system: Spot size predictions by application of the WISE code"Raimondi L, Svetina C, Mahne N, Cocco D, Abrami A, De Marco M, Fava C, Gerusina S, Gobessi R, Capotondi F, Pedersoli E, Kiskinova M, De Ninno G, Zeitoun P, Dovillaire G, Lambert G, Boutu W, Merdji H, Gonzalez AI, Gauthier D and Zangrando M, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, MAY 11, 2013. Vol. 710, pp. 131-138. ELSEVIER SCIENCE BV - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: FERMI@Elettra, the first seeded EUV-SXR free electron laser (FEL) facility located at Elettra Sincrotrone Trieste has been conceived to provide very short (10-100 fs) pulses with ultrahigh peak brightness and wavelengths from 100 nm to 4 nm. A section fully dedicated to the photon transport and analysis diagnostics, named PADReS, has already been installed and commissioned. Three of the beamlines, EIS-TIMEX, DiProl and LDM, installed after the PADReS section, are in advanced commissioning state and will accept the first users in December 2012. These beam lines employ active X-ray optics in order to focus the FEL beam as well as to perform a controlled beam-shaping at focus. Starting from mirror surface metrology characterization, it is difficult to predict the focal spot shape applying only methods based on geometrical optics such as the ray tracing. Within the geometrical optics approach one cannot take into account the diffraction effect from the optics edges, i.e. the aperture diffraction, and the impact of different surface spatial wavelengths to the spot size degradation. Both these effects are strongly dependent on the photon beam energy and mirror incident angles. We employed a method based on physical optics, which applies the Huygens-Fresnel principle to reflection (on which the WISE code is based). In this work we report the results of the first measurements of the focal spot in the DiProl beamline end-station and compare them to the predictions computed with Shadow code and WISE code, starting from the mirror surface profile characterization. (c) 2012 Elsevier B.V. All rights reserved. BibTeX: @article{Raimondi2013, author = {Raimondi, L. and Svetina, C. and Mahne, N. and Cocco, D. and Abrami, A. and De Marco, M. and Fava, C. and Gerusina, S. and Gobessi, R. and Capotondi, F. and Pedersoli, E. and Kiskinova, M. and De Ninno, G. and Zeitoun, P. and Dovillaire, G. and Lambert, G. and Boutu, W. and Merdji, H. and Gonzalez, A. I. and Gauthier, D. and Zangrando, M.}, title = {Microfocusing of the FERMI@Elettra FEL beam with a K-B active optics system: Spot size predictions by application of the WISE code}, journal = {NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, publisher = {ELSEVIER SCIENCE BV}, year = {2013}, volume = {710}, pages = {131-138}, url = {http://apps.webofknowledge.com/full_record.do?product=WOS&search_mode=GeneralSearch&qid=4&SID=S2moz4yDiJiWnQm5AkK&page=1&doc=3}, doi = {10.1016/j.nima.2012.11.039} }  "High-energy femtosecond laser pulse compression in single- and multi-ionization regime of rare gases: experiment versus theory"Auguste T, Fourcade Dutin C, Dubrouil A, Gobert O, Hort O, Mével E, Petit S, Constant E and Descamps D, APPL PHYS B-LASERS O. Vol. 111(1), pp. 75-87. Springer-Verlag - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report experimental and numerical results on the post-compression of 40 fs duration pulses down to 10 fs at high energy level (multi-mJ). The spectral broadening is achieved through the self-phase modulation resulting from optical-field-ionization of different noble gases (He, Ne, Ar) by the 40-fs laser pulse propagating in a low-pressure gas-filled hollow capillary. We discuss the influence of the multi-ionization dynamics, through the gas dependence, on the laser energy carried by the capillary, as well as on the duration and temporal shape of the post-compressed pulses. In all the different experimental conditions investigated in this article (pressures and gases used), the experimental data is in good agreement with the numerical results from a three-dimension propagation code. Through this study, we demonstrate the robustness of the proposed post-compression technique with regard to multi-ionization, indicating that it can be used on a large intensity range by judiciously choosing the gas. BibTeX: @article{AugusteAPB2013, author = {Auguste, T. and Fourcade Dutin, C. and Dubrouil, A. and Gobert, O. and Hort, O. and Mével, E. and Petit, S. and Constant, E. and Descamps, D.}, title = {High-energy femtosecond laser pulse compression in single- and multi-ionization regime of rare gases: experiment versus theory}, journal = {APPL PHYS B-LASERS O}, publisher = {Springer-Verlag}, year = {2013}, volume = {111}, number = {1}, pages = {75-87}, url = {http://dx.doi.org/10.1007/s00340-012-5309-x}, doi = {10.1007/s00340-012-5309-x} }  "Linked attosecond phase interferometry for molecular frame measurements"Bertrand JB, Wörner HJ, Salières P, Villeneuve DM and Corkum PB, NAT PHYS. Vol. 9, pp. 174?178 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: High-harmonic spectroscopy uses attosecond techniques to measure single-atom or molecule photorecombination cross-sections. Whereas the amplitude of the extreme-ultraviolet light is easily measurable, the phase is more challenging to access. However, the phase contains information necessary for tomographic imaging of the molecular orbital wavefunction with attosecond-ĺngström resolution. Present techniques cannot simultaneously measure the phase as a function of molecular angle and photon frequency, which is necessary for a full reconstruction of the wavefunction. We overcome this limitation with an all-optical method that does not require any ad hoc assumptions about the phase. We apply it to record the full phase map of aligned bromine molecules relative to reference xenon atoms. It allows us to resolve, both spectrally and angularly, the participation of multiple molecular orbitals, and infer a phase of ionization. This method opens a path to time-resolved molecular orbital tomography. BibTeX: @article{BertrandNP2013, author = {J. B. Bertrand and H. J. Wörner and P. Sali?res and D. M. Villeneuve and P. B. Corkum}, title = {Linked attosecond phase interferometry for molecular frame measurements}, journal = {NAT PHYS}, year = {2013}, volume = {9}, pages = {174?178}, url = {http://www.nature.com/nphys/journal/v9/n3/full/nphys2540.html}, doi = {10.1038/nphys2540} }  "Role of Rotational Wave Packets in Strong Field Experiments"Weber S-J, Oppermann M and Marangos J-P, Phys. Rev. Lett., Vol. 111(26), pp. 263601-. American Physical Society - December, (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: Complex revival features of rotational wave packets are obtained from the interplay of a molecular rotational distribution and a measured physical observable. The analysis of the measured temporal behavior can be used to retrieve either one or both quantities. We show here the first observation of high order fractional revival (up to 1/12 in CO2) using time-of-flight measurements of ion yields leading to the information required for full reconstruction of the rotational wave packet. We further show via an analysis of higher order fractional revivals in high harmonic generation that new information on the participating ionic channels can be clearly identified, showing the general implication of our results. BibTeX: @article{Weber2013, author = {Weber, S-J. and Oppermann, M. and Marangos, J-P.}, title = {Role of Rotational Wave Packets in Strong Field Experiments}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {2013}, volume = {111}, number = {26}, pages = {263601--}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.111.263601}, doi = {10.1103/PhysRevLett.111.263601} }  "Molecular orbital tomography from multi-channel harmonic emission in N2"Diveki Z, Guichard R, Caillat J, Camper A, Haessler S, Auguste T, Ruchon T, Carré B, Maquet A, Taïeb R and Salières P, CHEM PHYS. Vol. 414(0), pp. 121 - 129 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: High-order harmonic generation in aligned molecules can be used as an ultrafast probe of molecular structure and dynamics. By characterizing the emitted signal, one can retrieve information about electronic and nuclear dynamics at the attosecond timescale. In this paper, we discuss the theoretical and experimental aspects of molecular orbital tomography in N2 and investigate the influence of multi-channel ionization on the orbital imaging. By analyzing the harmonics’ spectral phase as a function of the driving laser intensity, we address two distinct cases, which in principle allow the orbital reconstruction. First, the contributions from two molecular orbitals could be disentangled in the real and imaginary parts of the measured dipole, allowing to reconstruct both orbitals. Second, by decreasing the driving laser intensity, the transition from a multi-channel to a single-channel ionization regime is shown. The latter approach paves the way towards the generalization of tomography to more complex systems. BibTeX: @article{DivekiCP2013, author = {Z. Diveki and R. Guichard and J. Caillat and A. Camper and S. Haessler and T. Auguste and T. Ruchon and B. Carré and A. Maquet and R. Taïeb and P. Salières}, title = {Molecular orbital tomography from multi-channel harmonic emission in N2}, journal = {CHEM PHYS }, year = {2013}, volume = {414}, number = {0}, pages = {121 - 129}, url = {http://www.sciencedirect.com/science/article/pii/S0301010412001401}, doi = {10.1016/j.chemphys.2012.03.021} }  "Impact of wave front and coherence optimization in coherent diffractive imaging"Ge X, Boutu W, Gauthier D, Wang F, Borta A, Barbrel B, Ducousso M, Gonzalez AI, Carré B, Guillaumet D, Perdrix M, Gobert O, Gautier J, Lambert G, Maia FRNC, Hajdu J, Zeitoun P and Merdji H, Opt Express., Vol. 21(9), pp. 11441-11447. OSA - May, (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present single shot nanoscale imaging using a table-top femtosecond soft X-ray laser harmonic source at a wavelength of 32 nm. We show that the phase retrieval process in coherent diffractive imaging critically depends on beam quality. Coherence and image fidelity are measured from single-shot coherent diffraction patterns of isolated nano-patterned slits. Impact of flux, wave front and coherence of the soft X-ray beam on the phase retrieval process and the image quality are discussed. After beam improvements, a final image reconstruction is presented with a spatial resolution of 78 nm (half period) in a single 20 fs laser harmonic shot. BibTeX: @article{GeOE2013, author = {X. Ge and W. Boutu and D. Gauthier and F. Wang and A. Borta and B. Barbrel and M. Ducousso and A. I. Gonzalez and B. Carré and D. Guillaumet and M. Perdrix and O. Gobert and J. Gautier and G. Lambert and F. R. N. C. Maia and J. Hajdu and P. Zeitoun and H. Merdji}, title = {Impact of wave front and coherence optimization in coherent diffractive imaging}, journal = {Opt Express}, publisher = {OSA}, year = {2013}, volume = {21}, number = {9}, pages = {11441--11447}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-21-9-11441}, doi = {10.1364/OE.21.011441} }  "Ellipticity dependence of strong field electron recollision for molecular structural imaging"Weber S, Oppermann M, Ivanov M and Marangos J, Journal of Modern Optics., In Journal of Modern Optics., August, 2013. Vol. 60(17), pp. 1379-1387. Taylor & Francis - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: AbstractNon-sequential double ionisation (NSDI) of CO in the tunnel ionisation regime is modelled and related to the Highest Occupied Molecular Orbital (HOMO) structure. Angularly resolved NSDI yields as a function of laser ellipticity is used to map nodal planes of the molecular orbital from which the electron is emitted. Peaks in the ellipticity dependence that are shifted to non-zero ellipticity and a finite degree of alignment are included in the model. Comparison with recent experiment reveals the presence of other orbitals contribution in CO when probed at 1350Â nm. BibTeX: @article{Weber2013a, author = {Weber, S.J. and Oppermann, M. and Ivanov, M.Yu. and Marangos, J.P.}, title = {Ellipticity dependence of strong field electron recollision for molecular structural imaging}, booktitle = {Journal of Modern Optics}, journal = {Journal of Modern Optics}, publisher = {Taylor & Francis}, year = {2013}, volume = {60}, number = {17}, pages = {1379--1387}, url = {http://dx.doi.org/10.1080/09500340.2013.814925}, doi = {10.1080/09500340.2013.814925} }  "Phase distortions of attosecond pulses produced by resonance-enhanced high harmonic generation"Haessler S, Strelkov V, Bom LBE, Khokhlova M, Gobert O, Hergott J-F, Lepetit F, Perdrix M, Ozaki T and Sali?res P, NEW J PHYS. Vol. 15(1), pp. 013051 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: Resonant enhancement of high harmonic generation can be obtained in plasmas containing ions with strong radiative transitions resonant with harmonic orders. The mechanism for this enhancement is still debated. We perform the first temporal characterization of the attosecond emission from a tin plasma under near-resonant conditions for two different resonance detunings. We show that the resonance considerably changes the relative phase of neighboring harmonics. For very small detunings, their phase locking may even be lost, evidencing strong phase distortions in the emission process and a modified attosecond structure. These features are well reproduced by our simulations, allowing their interpretation in terms of the phase of the recombination dipole moment. BibTeX: @article{HaesslerNJP2013, author = {S Haessler and V Strelkov and L B Elouga Bom and M Khokhlova and O Gobert and J-F Hergott and F Lepetit and M Perdrix and T Ozaki and P Sali?res}, title = {Phase distortions of attosecond pulses produced by resonance-enhanced high harmonic generation}, journal = {NEW J PHYS}, year = {2013}, volume = {15}, number = {1}, pages = {013051}, url = {http://stacks.iop.org/1367-2630/15/i=1/a=013051}, doi = {10.1088/1367-2630/15/1/013051} }  "Photonic streaking of attosecond pulse trains"Kim KT, Zhang C, Ruchon T, Hergott J-F, Auguste T, Villeneuve DM, Corkum PB and Quéré F, NAT PHOTONICS. Vol. Accepted - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: High harmonic radiation, produced when intense laser pulses interact with matter, is composed of a train of attosecond pulses. Individual pulses in this train carry information on ultrafast dynamics that vary from one half-optical-cycle to the next. Here, we demonstrate an all-optical photonic streaking measurement that provides direct experimental access to each attosecond pulse by mapping emission time onto propagation angle. This is achieved by inducing an ultrafast rotation of the instantaneous laser wavefront at the focus. We thus time-resolve attosecond pulse train generation, and hence the dynamics in the nonlinear medium itself. We apply photonic streaking to harmonic generation in gases and directly observe, for the first time, the influence of non-adiabatic electron dynamics and plasma formation on the generated attosecond pulse train. These experimental and numerical results also provide the first evidence of the generation of attosecond lighthouses in gases, which constitute ideal sources for attosecond pump?probe spectroscopy. BibTeX: @article{KimNP2013, author = {Kyung Taec Kim and Chunmei Zhang and Thierry Ruchon and Jean-Francois Hergott and Thierry Auguste andD. M. Villeneuve and P. B. Corkum and F. Quéré}, title = {Photonic streaking of attosecond pulse trains}, journal = {NAT PHOTONICS}, year = {2013}, volume = {Accepted}, url = {http://www.nature.com/nphoton/journal/v7/n8/full/nphoton.2013.170.html?WT.ec_id=NPHOTON-201308}, doi = {10.1038/nphoton.2013.170} }  "Microfocusing of the FERMI@Elettra FEL beam with a K-B active optics system: Spot size predictions by application of the WISE code "Raimondi L, Svetina C, Mahne N, Cocco D, Abrami A, Marco MD, Fava C, Gerusina S, Gobessi R, Capotondi F, Pedersoli E, Kiskinova M, Ninno GD, Zeitoun P, Dovillaire G, Lambert G, Boutu W, Merdji H, Gonzalez A, Gauthier D and Zangrando M, NUCL INSTRUM METH A. Vol. 710(0), pp. 131 - 138 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: FERMI@Elettra, the first seeded EUV-SXR free electron laser (FEL) facility located at Elettra Sincrotrone Trieste has been conceived to provide very short (10-100 fs) pulses with ultrahigh peak brightness and wavelengths from 100 nm to 4 nm. A section fully dedicated to the photon transport and analysis diagnostics, named PADReS, has already been installed and commissioned. Three of the beamlines, EIS-TIMEX, DiProI and LDM, installed after the PADReS section, are in advanced commissioning state and will accept the first users in December 2012. These beam lines employ active X-ray optics in order to focus the FEL beam as well as to perform a controlled beam-shaping at focus.Starting from mirror surface metrology characterization, it is difficult to predict the focal spot shape applying only methods based on geometrical optics such as the ray tracing. Within the geometrical optics approach one cannot take into account the diffraction effect from the optics edges, i.e. the aperture diffraction, and the impact of different surface spatial wavelengths to the spot size degradation. Both these effects are strongly dependent on the photon beam energy and mirror incident angles.We employed a method based on physical optics, which applies the Huygens?Fresnel principle to reflection (on which the WISE code is based). In this work we report the results of the first measurements of the focal spot in the DiProI beamline end-station and compare them to the predictions computed with Shadow code and WISE code, starting from the mirror surface profile characterization. BibTeX: @article{RaimondiNIMPRSA2013, author = {L. Raimondi and C. Svetina and N. Mahne and D. Cocco and A. Abrami and M. De Marco and C. Fava and S. Gerusina and R. Gobessi and F. Capotondi and E. Pedersoli and M. Kiskinova and G. De Ninno and P. Zeitoun and G. Dovillaire and G. Lambert and W. Boutu and H. Merdji and A.I. Gonzalez and D. Gauthier and M. Zangrando}, title = {Microfocusing of the FERMI@Elettra FEL beam with a K?B active optics system: Spot size predictions by application of the WISE code }, journal = {NUCL INSTRUM METH A}, year = {2013}, volume = {710}, number = {0}, pages = {131 - 138}, note = {The 4th international workshop on Metrology for X-ray Optics, Mirror Design, and Fabrication}, url = {http://www.sciencedirect.com/science/article/pii/S0168900212013769}, doi = {10.1016/j.nima.2012.11.039} }  "Molecular internal dynamics studied by quantum path interferences in high order harmonic generation "Zair A, Siegel T, Sukiasyan S, Risoud F, Brugnera L, Hutchison C, Diveki Z, Auguste T, Tisch JW, Salières P, Ivanov MY and Marangos JP, CHEM PHYS. Vol. 414(0), pp. 184 - 191 - (2013). [Abstract] [BibTeX] [DOI] [URL] Abstract: We investigate how short and long electron trajectory contributions to high harmonic emission and their interferences give access to information about intra-molecular dynamics. In the case of unaligned molecules, we show experimental evidence that the long trajectory contribution is more dependent upon the molecular species than the short one, providing a high sensitivity to cation nuclear dynamics from 100's of as to a few fs after ionisation. Using theoretical approaches based on the strong field approximation and numerical integration of the time dependent Schrödinger equation, we examine how quantum path interferences encode electronic motion when the molecules are aligned. We show that the interferences are dependent upon which ionisation channels are involved and any superposition between them. In particular, quantum path interferences can encode signatures of electron dynamics if the laser field drives a coupling between the channels. Hence, molecular quantum path interferences are a promising method for attosecond spectroscopy, allowing the resolution of ultra-fast charge migration in molecules after ionisation in a self-referenced manner. BibTeX: @article{ZairCP2013, author = {Amelle Zair and Thomas Siegel and Suren Sukiasyan and Francois Risoud and Leonardo Brugnera and Christopher Hutchison and Zsolt Diveki and Thierry Auguste and John W.G. Tisch and Pascal. Sali?res and Misha Y. Ivanov and Jonathan P. Marangos}, title = {Molecular internal dynamics studied by quantum path interferences in high order harmonic generation }, journal = {CHEM PHYS}, year = {2013}, volume = {414}, number = {0}, pages = {184 - 191}, note = {Attosecond spectroscopy }, url = {http://www.sciencedirect.com/science/article/pii/S0301010412004739}, doi = {10.1016/j.chemphys.2012.12.022} }  2012 "Driving-frequency scaling of high-harmonic quantum paths"Auguste T, Catoire F, Agostini P, DiMauro LF, Chirila CC, Yakovlev VS and Salières P, NEW J PHYS. Vol. 14(10), pp. 103014 (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: We have developed an analytical theory explaining how the single-atom efficiency of high-harmonic generation scales with laser frequency, and verified this by numerically solving the time-dependent Schrödinger equation in three spatial dimensions. According to our saddle-point analysis of quantum paths, the imaginary part of the action has a significant impact on the scaling law. Furthermore, we found that the scaling law depends on the analytical properties of the ground??“continuum transition matrix element. Our analysis elucidates how the relative contributions of different quantum orbits and their relative phases vary with the driving laser frequency and how the resulting quantum-path interferences in high-harmonic spectra can be controlled with an attosecond accuracy. BibTeX: @article{AugusteNJP2012, author = {T Auguste and F Catoire and P Agostini and L F DiMauro and C C Chirila and V S Yakovlev and P Salières}, title = {Driving-frequency scaling of high-harmonic quantum paths}, journal = {NEW J PHYS}, year = {2012}, volume = {14}, number = {10}, pages = {103014}, url = {http://stacks.iop.org/1367-2630/14/i=10/a=103014}, doi = {10.1088/1367-2630/14/10/103014} }  "Application of optical-field-ionization-induced spectral broadening in helium gas to the postcompression of high-energy femtosecond laser pulses"Auguste T, Gobert O, Dutin CF, Dubrouil A, Mével E, Petit S, Constant E and Descamps D, J Opt Soc Am B., Vol. 29(6), pp. 1277-1286. OSA - Jun, (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report a detailed numerical study on the postcompression of high-energy (~30 mJ) femtosecond laser pulses (~40 fs), using the spectral broadening induced by optical-field ionization of a low-pressure helium gas in a capillary. Our numerical results are in very good agreement with previously published experimental data on spectral shapes, transmitted energies and recompressed pulse durations in the full range of laser energies and gas pressures investigated. Then, we calculate the performances of the method with shorter input pulses (~20 fs) and demonstrate that few optical cycles recompressed pulses with 5 to 8.5 mJ energy could then be achieved. BibTeX: @article{AugusteJOSAB12, author = {Thierry Auguste and Oliver Gobert and Coralie Fourcade Dutin and Antoine Dubrouil and Eric Mével and Stéphane Petit and Eric Constant and Dominique Descamps}, title = {Application of optical-field-ionization-induced spectral broadening in helium gas to the postcompression of high-energy femtosecond laser pulses}, journal = {J Opt Soc Am B}, publisher = {OSA}, year = {2012}, volume = {29}, number = {6}, pages = {1277--1286}, url = {http://josab.osa.org/abstract.cfm?URI=josab-29-6-1277}, doi = {10.1364/JOSAB.29.001277} }  "Molecular frame photoemission in dissociative ionization of H2 and D2 induced by high harmonic generation femtosecond XUV pulses"Billaud P, Géléoc M, Picard YJ, Veyrinas K, Hergott JF, Poullain SM, Breger P, Ruchon T, Roulliay M, Delmotte F, Lepetit F, Huetz A, Carré B and Dowek D, J PHYS B-AT MOL OPT. Vol. 45(19), pp. 194013 - (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report the first results of molecular frame photoelectron emission for dissociative photoionization (DPI) of H2 and D2 molecules induced by a spectrally filtered single high harmonic of a few femtosecond duration, using coincident electron-ion velocity vector correlation techniques. For the studied photon energies around 32 eV, where the resonant excitation of the Q1 and Q2 doubly excited states occurs, autoionization and nuclear dynamics are coupled on a few femtosecond timescale, giving rise to quantum interferences. Molecular frame photoelectron angular distributions (MFPADs), traced as a function of the kinetic energy release of the atomic fragments, provide the most sensitive observables for such complex dynamics. These results compare well with recent spectrally resolved experiments using synchrotron radiation which are also reported. As a novel XUV light source running at multi-kHz repetition rate and synchronized with laser pulses, high-order harmonic generation (HHG) opens new possibilities for extending these investigations to time-resolved studies at the femtosecond scale. BibTeX: @article{BillaudJPB2012, author = {P Billaud and M Géléoc and Y J Picard and K Veyrinas and J F Hergott and S Marggi Poullain and P Breger and T Ruchon and M Roulliay and F Delmotte and F Lepetit and A Huetz and B Carré and D Dowek}, title = {Molecular frame photoemission in dissociative ionization of H2 and D2 induced by high harmonic generation femtosecond XUV pulses}, journal = {J PHYS B-AT MOL OPT}, year = {2012}, volume = {45}, number = {19}, pages = {194013}, url = {http://stacks.iop.org/0953-4075/45/i=19/a=194013}, doi = {10.1088/0953-4075/45/19/194013} }  "Statistical analysis of fragmentation channels of small multicharged molecular ions"Cornaggia C, J PHYS B-AT MOL OPT. Vol. 45(8), pp. 085602 - (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: Laser-induced multiple ionization and Coulomb explosion of small molecules may lead on average to more than one fragmentation event per laser pulse even when experiments are performed at very low gas pressures in the 108-109 mbar range. In order to bypass the failure of coincidence techniques in this case, Frasinski et al (1989 Science 246 1029) proposed an alternative technique denoted covariance mapping based on correlated fluctuations of digitized ion signals coming from identical fragmentation channels. A probabilistic approach of the detected signals shows that covariance eliminates false coincidences due to fragments from different fragmentation channels, and false coincidences due to fragments from the same fragmentation channel, but which do not originate from the same unimolecular fragmentation events. The analysis is extended to devices which do not accept more than one count per time-of-flight bin such as multichannel scalers or time-to-digital converters. It is still possible to remove false coincidences using covariance but with a formulation which is noticeably different from the initial proposal for digitized signals. BibTeX: @article{Cornaggia2012, author = {C Cornaggia}, title = {Statistical analysis of fragmentation channels of small multicharged molecular ions}, journal = {J PHYS B-AT MOL OPT}, year = {2012}, volume = {45}, number = {8}, pages = {085602}, url = {http://stacks.iop.org/0953-4075/45/i=8/a=085602}, doi = {10.1088/0953-4075/45/8/085602} }  "Spectrally resolved multi-channel contributions to the harmonic emission in N2",Diveki Z, Camper A, Haessler S, Auguste T, Ruchon T, Carré B, Salières P, Guichard R, Caillat J, Maquet A and Taïeb R, New J Phys. Vol. 14(2), pp. 023062 - (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: When generated in molecules, high-order harmonics can be emitted through different ionization channels. The coherent and ultrafast electron dynamics occurring in the ion during the generation process is directly imprinted in the harmonic signal, i.e. in its amplitude and spectral phase. In aligned N2 molecules, we find evidence for a fast variation of this phase as a function of the harmonic order when varying the driving laser intensity. Basing our analysis on a three-step model, we find that this phase variation is a signature of transitions from a single- to a multi-channel regime. In particular, we show that significant nuclear dynamics may occur in the ionization channels on the attosecond timescale, affecting both the amplitude and the phase of the harmonic signal. BibTeX: @article{DivekiNJP2012, author = {Z Diveki and A Camper and S Haessler and T Auguste and T Ruchon and B Carré and P Salières and R Guichard and J Caillat and A Maquet and R Taïeb}, title = {Spectrally resolved multi-channel contributions to the harmonic emission in N 2}, journal = {New J Phys}, year = {2012}, volume = {14}, number = {2}, pages = {023062}, url = {http://stacks.iop.org/1367-2630/14/i=2/a=023062}, doi = {10.1088/1367-2630/14/2/023062} }  "Femtosecond envelope of the high-harmonic emission from ablation plasmas"Haessler S, Elouga Bom LB, Gobert O, Hergott J-F, Lepetit F, Perdrix M, Carré B, Ozaki T and Salières P, Journal of Physics B Atomic Molecular Physics., Vol. 45(7), pp. 074012 - April, (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: We characterize the temporal profile of the high-order harmonic emission from ablation plasma plumes using cross-correlations with the infrared (IR) laser beam provided by two-photon harmonic+IR ionization of rare gas atoms. We study both non-resonant plasmas (lead, gold and chrome) and resonant plasmas (indium and tin), i.e. plasmas presenting in the singly charged ions a strong radiative transition coinciding with a harmonic order. The cross-correlation traces are found to be very similar for all harmonic orders and all plasma targets. The recovered harmonic pulse durations are very similar to the driving laser, with a tendency towards being shorter, demonstrating that the emission is a directly laser-driven process even in the case of resonant harmonics. This provides a valuable input for theories describing resonant-harmonic emission and opens the perspective of a very high flux tabletop XUV source for applications. BibTeX: @article{HaesslerJPB2012, author = {Haessler, S. and Elouga Bom, L.~B. and Gobert, O. and Hergott, J.-F. and Lepetit, F. and Perdrix, M. and Carré, B. and Ozaki, T. and Salières, P.}, title = {Femtosecond envelope of the high-harmonic emission from ablation plasmas}, journal = {Journal of Physics B Atomic Molecular Physics}, year = {2012}, volume = {45}, number = {7}, pages = {074012}, url = {http://iopscience.iop.org/0953-4075/45/7/074012/}, doi = {10.1088/0953-4075/45/7/074012} }  "Imaging orbitals with attosecond and Ångström resolutions: toward attochemistry?"Salières P, Maquet A, Haessler S, Caillat J and Taïeb R, REP PROG PHYS. Vol. 75(6), pp. 062401 - (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: The recently developed attosecond light sources make the investigation of ultrafast processes in matter possible with unprecedented time resolution. It has been proposed that the very mechanism underlying the attosecond emission allows the imaging of valence orbitals with Ångström space resolution. This controversial idea together with the possibility of combining attosecond and Ångström resolutions in the same measurements has become a hot topic in strong-field science. Indeed, this could provide a new way to image the evolution of the molecular electron cloud during, e.g. a chemical reaction in "real time". Here we review both experimental and theoretical challenges raised by the implementation of these prospects. In particular, we show how the valence orbital structure is encoded in the spectral phase of the recombination dipole moment calculated for Coulomb scattering states, which allows a tomographic reconstruction of the orbital using first-order corrections to the plane-wave approach. The possibility of disentangling multi-channel contributions to the attosecond emission is discussed as well as the necessary compromise between the temporal and spatial resolutions. BibTeX: @article{SalieresRPP2012, author = {P Sali?res and A Maquet and S Haessler and J Caillat and R Ta?eb}, title = {Imaging orbitals with attosecond and ?ngström resolutions: toward attochemistry?}, journal = {REP PROG PHYS}, year = {2012}, volume = {75}, number = {6}, pages = {062401}, url = {http://stacks.iop.org/0034-4885/75/i=6/a=062401}, doi = {10.1088/0034-4885/75/6/062401} }  "Laser-induced ultrafast demagnetization in the presence of a nanoscale magnetic domain network"Vodungbo B, Gautier J, Lambert G, Sardinha AB, Lozano M, Sebban S, Ducousso M, Boutu W, Li K, Tudu B, Tortarolo M, Hawaldar R, Delaunay R, Lopez-Flores V, Arabski J, Boeglin C, Merdji H, Zeitoun P and Lüning J, Nat Commun. Vol. 3, pp. 999 - (2012). [Abstract] [BibTeX] [DOI] [URL] Abstract: Femtosecond magnetization phenomena have been challenging our understanding for over a decade. Most experiments have relied on infrared femtosecond lasers, limiting the spatial resolution to a few micrometres. With the advent of femtosecond X-ray sources, nanometric resolution can now be reached, which matches key length scales in femtomagnetism such as the travelling length of excited 'hot' electrons on a femtosecond timescale. Here we study laser-induced ultrafast demagnetization in [Co/Pd]30 multilayer films, which, for the first time, achieves a spatial resolution better than 100 nm by using femtosecond soft X-ray pulses. This allows us to follow the femtosecond demagnetization process in a magnetic system consisting of alternating nanometric domains of opposite magnetization. No modification of the magnetic structure is observed, but, in comparison with uniformly magnetized systems of similar composition, we find a significantly faster demagnetization time. We argue that this may be caused by direct transfer of spin angular momentum between neighbouring domains. BibTeX: @article{VodungboNatComm12, author = {Vodungbo, Boris and Gautier, Julien and Lambert, Guillaume and Sardinha, Anna Barszczak and Lozano, Magali and Sebban, Stéphane and Ducousso, Mathieu and Boutu, Willem and Li, Kaigong and Tudu, Bharati and Tortarolo, Marina and Hawaldar, Ranjit and Delaunay, Renaud and Lopez-Flores, Victor and Arabski, Jacek and Boeglin, Christine and Merdji, Hamed and Zeitoun, Philippe and Lüning, Jan}, title = {Laser-induced ultrafast demagnetization in the presence of a nanoscale magnetic domain network}, journal = {Nat Commun}, year = {2012}, volume = {3}, pages = {999}, url = {http://dx.doi.org/10.1038/ncomms2007}, doi = {10.1038/ncomms2007} }  2011 "Attosecond emission from chromium plasma"Bom LBE, Haessler S, Gobert O, Perdrix M, Lepetit F, Hergott J-F, Carré B, Ozaki T and Salières P, Opt Express., Vol. 19(4), pp. 3677-3685. OSA -Feb, (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present the first measurement of the attosecond emission generated from underdense plasma produced on a solid target. We generate high-order harmonics of a femtosecond Ti:sapphire laser focused in a weakly ionized underdense chromium plasma. Using the Reconstruction of Attosecond Beating by Interference of Two-photon Transitions'' (RABITT) technique, we show that the 11th to the 19th harmonic orders form in the time domain an attosecond pulse train with each pulse having 300 as duration, which is only 1.05 times the theoretical Fourier transform limit. Measurements reveal a very low positive group delay dispersion of 4200 as2. Beside its fundamental interest, high-order harmonic generation in plasma plumes could thus provide an intense source of attosecond pulses for applications. BibTeX: @article{BomOE2011, author = {L. B. Elouga Bom and S. Haessler and O. Gobert and M. Perdrix and F. Lepetit and J.-F. Hergott and B. Carré and T. Ozaki and P. Salières}, title = {Attosecond emission from chromium plasma}, journal = {Opt Express}, publisher = {OSA}, year = {2011}, volume = {19}, number = {4}, pages = {3677--3685}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-4-3677}, doi = {10.1364/OE.19.003677} }  "Control of the attosecond synchronization of XUV radiation with phase-optimized mirrors"Bourassin-Bouchet C, Diveki Z, de Rossi S, English E, Meltchakov E, Gobert O, Guénot D, Carré B, Delmotte F, Salières P and Ruchon T, Opt Express., Vol. 19(4), pp. 3809-3817. OSA - Feb, (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: We report on the advanced amplitude and phase control of attosecond radiation allowed by specifically-designed multilayer XUV mirrors. We first demonstrate that such mirrors can compensate for the intrinsic chirp of the attosecond emission over a large bandwidth of more than 20 eV. We then show that their combination with metallic foils introduces a third-order dispersion that is adjustable through the mirror's incidence angle. This results in a controllable beating allowing the radiationto be shaped from a single to a series of sub-100 as pulses. BibTeX: @article{BourassinBouchetOE2011, author = {C. Bourassin-Bouchet and Z. Diveki and S. de Rossi and E. English and E. Meltchakov and O. Gobert and D. Guénot and B. Carré and F. Delmotte and P. Salières and T. Ruchon}, title = {Control of the attosecond synchronization of XUV radiation with phase-optimized mirrors}, journal = {Opt Express}, publisher = {OSA}, year = {2011}, volume = {19}, number = {4}, pages = {3809--3817}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-4-3809}, doi = {10.1364/OE.19.003809} }  "High-order-harmonic generation in gas with a flat-top laser beam"Boutu W, Auguste T, Boyko O, Sola I, Balcou P, Binazon L, Gobert O, Merdji H, Valentin C, Constant E, Mével E and Carré B, PHYS REV A., Vol. 84, pp. 063406. American Physical Society - Dec, (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present experimental and numerical results on high-order-harmonic generation with a flat-top laser beam. We show that a simple binary tunable phase plate, made of two concentric glass plates, can produce a flat-top profile at the focus of a Gaussian infrared beam. Both experiments and numerical calculations show that there is a scaling law between the harmonic generation efficiency and the increase of the generation volume. BibTeX: @article{BoutuPRA2011b, author = {Boutu, W. and Auguste, T. and Boyko, O. and Sola, I. and Balcou, Ph. and Binazon, L. and Gobert, O. and Merdji, H. and Valentin, C. and Constant, E. and Mével, E. and Carré, B.}, title = {High-order-harmonic generation in gas with a flat-top laser beam}, journal = {PHYS REV A}, publisher = {American Physical Society}, year = {2011}, volume = {84}, pages = {063406}, url = {http://link.aps.org/doi/10.1103/PhysRevA.84.063406}, doi = {10.1103/PhysRevA.84.063406} }  "Scaling of the generation of high-order harmonics in large gas media with focal length"Boutu W, Auguste T, Caumes JP, Merdji H and Carré B, PHYS REV A., Vol. 84, pp. 053819. American Physical Society - Nov, (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: We present theoretical and experimental results on high-order harmonic generation in a low-density few-centimeter-long gas medium (Lmed≤10 cm). We study the dependence with focal length of harmonic efficiency. Theoretically, we consider in detail the generation of the 25th harmonic of a short pulse Ti:sapphire laser in argon. Within the strong-field approximation for the atomic dipole, and a complete account of the macroscopic propagation, we compute the number of photons produced as a function of the medium parameters and the focusing conditions. The simulations show that, at constant intensity, the emission of the 25th harmonic scales with the focal length as ~f4 at low pressure (P=2 Torr) and as ~f 6 at higher pressure (P=5 Torr). At constant laser energy, we find that the harmonic signal scales approximately as f2 at low pressure and as f4 at higher pressure. Those numerical results are compared with experimental data. BibTeX: @article{BoutuPRA2011, author = {Boutu, W. and Auguste, T. and Caumes, J. P. and Merdji, H. and Carré, B.}, title = {Scaling of the generation of high-order harmonics in large gas media with focal length}, journal = {PHYS REV A}, publisher = {American Physical Society}, year = {2011}, volume = {84}, pages = {053819}, url = {http://link.aps.org/doi/10.1103/PhysRevA.84.053819}, doi = {10.1103/PhysRevA.84.053819} }  "Attosecond Resolved Electron Release in Two-Color Near-Threshold Photoionization of N-2"Caillat J, Maquet A, Haessler S, Fabre B, Ruchon T, Salières P, Mairesse Y and Taïeb R, Phys Rev Lett., Vol. 106(9), pp. 093002 - MARs, (2011). [Abstract] [BibTeX] [DOI] Abstract: We have simulated two-color photoionization of N-2 by solving the time-dependent Schrodinger equation with a simple model accounting for the correlated vibronic dynamics of the molecule and of the ion N-2(+). Our results, in very good agreement with recent experiments [Haessler et al., Phys. Rev. A 80, 011404 (2009)], show how a resonance embedded in the molecular continuum dramatically affects the phases of the two-photon transition amplitudes. In addition, we introduce a formal relation between these measurable phases and the photoelectron release time, opening the way to attosecond time-resolved measurements, equivalent to double-slit experiments in the time domain. BibTeX: @article{CaillatPRL2011, author = {Caillat, Jeremie and Maquet, Alfred and Haessler, Stefan and Fabre, Baptiste and Ruchon, Thierry and Salières, Pascal and Mairesse, Yann and Taïeb, Richard}, title = {Attosecond Resolved Electron Release in Two-Color Near-Threshold Photoionization of N-2}, journal = {Phys Rev Lett}, year = {2011}, volume = {106}, number = {9}, pages = {093002}, doi = {10.1103/PhysRevLett.106.093002} }  "Nonredundant array of apertures to measure the spatial coherence in two dimensions with only one interferogram"GonzAlez AI and Mejía Y, J. Opt. Soc. Am. A., Vol. 28(6), pp. 1107-1113. OSA - Jun, (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: We propose to use a mask with a nonredundant array (NRA) of multiple apertures to measure spatial coherence in two dimensions. The spatial distribution of the apertures in the mask is made in such a way that we obtain a quasi-uniform sampling in the coherence domain. The spatial coherence is obtained by Fourier transform of the interferogram generated by the mask when it is illuminated by the light field under analysis. BibTeX: @article{GonzalezJOSA2011, author = {Aura I. GonzAlez and Yobani Mejía}, title = {Nonredundant array of apertures to measure the spatial coherence in two dimensions with only one interferogram}, journal = {J. Opt. Soc. Am. A}, publisher = {OSA}, year = {2011}, volume = {28}, number = {6}, pages = {1107--1113}, url = {http://josaa.osa.org/abstract.cfm?URI=josaa-28-6-1107}, doi = {10.1364/JOSAA.28.001107} }  "Self-referenced spectral interferometry cross-checked with SPIDER on sub-15fs pulses"Grabielle S, Moulet A, Forget N, Crozatier V, Coudreau S, Herzog R, Oksenhendler T, Cornaggia C and Gobert O, NUCL INSTRUM METH A., Vol. 653, pp. 121. Elsevier - Jan, (2011). [BibTeX] [URL] BibTeX: @article{2011_NIMPhysResA653_121_Grabielle, author = {S. Grabielle and A. Moulet and N. Forget and V. Crozatier and S. Coudreau and R. Herzog and T. Oksenhendler and C. Cornaggia and O. Gobert}, title = {Self-referenced spectral interferometry cross-checked with SPIDER on sub-15fs pulses}, journal = {NUCL INSTRUM METH A}, publisher = {Elsevier}, year = {2011}, volume = {653}, pages = {121}, url = {www.elsevier.com/locate/nima} }  "Self-probing of molecules with high harmonic generation"Haessler S, Caillat J and Salières P, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 44(20), pp. 203001 (2011). [Abstract] [BibTeX] [URL] Abstract: This tutorial presents the most important aspects of the molecular self-probing paradigm, which views the process of high harmonic generation as 'a molecule being probed by one of its own electrons'. Since the properties of the electron wavepacket acting as a probe allow a combination of attosecond and Ă…ngstrĂ¶m resolutions in measurements, this idea bears great potential for the observation, and possibly control, of ultrafast quantum dynamics in molecules at the electronic level. Theoretical as well as experimental methods and concepts at the basis of self-probing measurements are introduced. Many of these are discussed as the example of molecular orbital tomography. BibTeX: @article{HaesslerJPB2011, author = {Haessler, S. and Caillat, J. and Salières, P.}, title = {Self-probing of molecules with high harmonic generation}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2011}, volume = {44}, number = {20}, pages = {203001}, url = {http://stacks.iop.org/0953-4075/44/i=20/a=203001} }  "High-Gain Harmonic-Generation Free-Electron Laser Seeded by Harmonics Generated in Gas"Labat M, Bellaveglia M, Bougeard M, Carré B, Ciocci F, Chiadroni E, Cianchi A, Couprie M-E, Cultrera L, Franco MD, Pirro GD, Drago A, Ferrario M, Filippetto D, Frassetto F, Gallo A, Garzella D, Gatti G, Giannessi L, Lambert G, Mostacci A, Petralia A, Petrillo V, Poletto L, Quattromini M, Rau J, Ronsivalle C, Sabia E, Serluca M, Spassovsky I, Surrenti V, Vaccarezza C and Vicario C, Phys Rev Lett. Vol. 107, pp. 224801 - (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: The injection of a seed in a free-electron laser (FEL) amplifier reduces the saturation length and improves the longitudinal coherence. A cascaded FEL, operating in the high-gain harmonic-generation regime, allows us to extend the beneficial effects of the seed to shorter wavelengths. We report on the first operation of a high-gain harmonic-generation free-electron laser, seeded with harmonics generated in gas. The third harmonics of a Ti:sapphire laser, generated in a gas cell, has been amplified and up-converted to its second harmonic (?rad=133??nm) in a FEL cascaded configuration based on a variable number of modulators and radiators. We studied the transition between coherent harmonic generation and superradiant regime, optimizing the laser performances with respect to the number of modulators and radiators. BibTeX: @article{M.Labat2011, author = {M. Labat and M. Bellaveglia and M. Bougeard and B. Carré and F. Ciocci and E. Chiadroni and A. Cianchi and M.-E. Couprie and L. Cultrera and M. Del Franco and G. Di Pirro and A. Drago and M. Ferrario and D. Filippetto and F. Frassetto and A. Gallo and D. Garzella and G. Gatti and L. Giannessi and G. Lambert and A. Mostacci and A. Petralia and V. Petrillo and L. Poletto and M. Quattromini and J.V. Rau and C. Ronsivalle and E. Sabia and M. Serluca and I. Spassovsky and V. Surrenti and C. Vaccarezza and C. Vicario}, title = {High-Gain Harmonic-Generation Free-Electron Laser Seeded by Harmonics Generated in Gas}, journal = {Phys Rev Lett}, year = {2011}, volume = {107}, pages = {224801}, url = {http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.107.224801}, doi = {10.1103/PhysRevLett.107.224801} }  "Ultrafast molecular imaging by laser-induced electron diffraction"Peters M, Nguyen-Dang TT, Cornaggia C, Saugout S, Charron E, Keller A and Atabek O, Phys Rev A., Vol. 83(5), pp. 051403 - MAY 31, (2011). [Abstract] [BibTeX] [DOI] Abstract: We address the feasibility of imaging geometric and orbital structures of a polyatomic molecule on an attosecond time scale using the laser-induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO2 molecule excited by a near-infrared few-cycle laser pulse. The molecular geometry (bond lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms. BibTeX: @article{PetersPRA2011, author = {Peters, M. and Nguyen-Dang, T. T. and Cornaggia, C. and Saugout, S. and Charron, E. and Keller, A. and Atabek, O.}, title = {Ultrafast molecular imaging by laser-induced electron diffraction}, journal = {Phys Rev A}, year = {2011}, volume = {83}, number = {5}, pages = {051403}, doi = {10.1103/PhysRevA.83.051403} }  "Modular EUV Source for the Next Generation Lithography"Sublemontier O, Rosset-Kos M, Ceccotti T, Hergott J-F, Auguste T, Normand D, Schmidt M, Beaumont F, Farcage D, Cheymol G, Caro J-ML, Cormont P, Mauchien P, Thro P-Y, Skrzypczak J, Muller S, Marquis E, Barthod B, Gaurand I, Davenet M and Bernard R, J LASER MICRO NANOEN. Vol. 6, pp. 113 - (2011). [Abstract] [BibTeX] [DOI] [URL] Abstract: The present work, performed in the frame of the EXULITE project, was dedicated to the design and characterization of a laser-plasma-produced extreme ultraviolet (EUV) source prototype at 13.5 nm for the next generation lithography. It was conducted in cooperation with two laboratories from CEA, ALCATEL and THALES. One of our approach originalities was the laser scheme modularity. Six Nd:YAG laser beams were focused at the same time on a xenon filament jet to generate the EUV emitting plasma. Multiplexing has important industrial advantages and led to interesting source performances in terms of in-band power, stability and angular emission properties with the filament jet target. A maximum conversion efficiency (CE) value of 0.44% in 2π sr and 2% band-width was measured, which corresponds to a maximum in band EUV mean power of 7.7 W at a repetition rate of 6 kHz. The EUV emission was found to be stable and isotropic in these conditions. BibTeX: @article{SublemontierJLM2011, author = {O. Sublemontier and M. Rosset-Kos and T. Ceccotti and J.-F. Hergott and T. Auguste and D. Normand and M. Schmidt and F. Beaumont and D. Farcage and G. Cheymol and J.-M. Le Caro and P. Cormont and P. Mauchien and P.-Y. Thro and J. Skrzypczak and S. Muller and E. Marquis and B. Barthod and I. Gaurand and M. Davenet and R. Bernard}, title = {Modular EUV Source for the Next Generation Lithography}, journal = {J LASER MICRO NANOEN}, year = {2011}, volume = {6}, pages = {113}, url = {http://hal-cea.archives-ouvertes.fr/hal-00658816}, doi = {10.2961/jlmn.2011.02.0004} }  2010 "Enhancements of rescattered electron yields in above-threshold ionization of molecules"Cornaggia C, Phys Rev A., Vol. 82(5), pp. 053410 - NOV 15, (2010). [Abstract] [BibTeX] [DOI] Abstract: In above-threshold ionization of rare-gas atoms, photoelectron spectra recorded in the 10(13)-10(14) W cm(-2) range exhibit enhancements in the rescattering plateaus that do not have a unified theoretical interpretation yet. Here an experimental search for such enhancements is reported in simple molecules with ionization potentials near those of rare-gas atoms such as H-2 and N-2 for argon and O-2 for xenon, and in other molecules such as CO2 and N2O. Only H-2 exhibits the enhancements previously observed in atoms. The H-2 particularity is interpreted in terms of its simpler ion structure and associated ionization paths compared with other molecules. BibTeX: @article{Cornaggia2010, author = {Cornaggia, C.}, title = {Enhancements of rescattered electron yields in above-threshold ionization of molecules}, journal = {Phys Rev A}, year = {2010}, volume = {82}, number = {5}, pages = {053410}, doi = {10.1103/PhysRevA.82.053410} }  "Auger Electron Angular Distribution of Double Core-Hole States in the Molecular Reference Frame"Cryan JP, Glownia JM, Andreasson J, Belkacem A, Berrah N, Blaga CI, Bostedt C, Bozek J, Buth C, DiMauro LF, Fang L, Gessner O, Guehr M, Hajdu J, Hertlein MP, Hoener M, Kornilov O, Marangos JP, March AM, McFarland BK, Merdji H, Petrovic VS, Raman C, Ray D, Reis D, Tarantelli F, Trigo M, White JL, White W, Young L, Bucksbaum PH and Coffee RN, Phys Rev Lett., Vol. 105(8), pp. 083004 - AUG 20, (2010). [Abstract] [BibTeX] [DOI] Abstract: The Linac Coherent Light Source free electron laser is a source of high brightness x rays, 2 x 10(11) photons in a similar to 5 fs pulse, that can be focused to produce double core vacancies through rapid sequential ionization. This enables double core vacancy Auger electron spectroscopy, an entirely new way to study femtosecond chemical dynamics with Auger electrons that probe the local valence structure of molecules near a specific atomic core. Using 1.1 keV photons for sequential x-ray ionization of impulsively aligned molecular nitrogen, we observed a rich single-site double core vacancy Auger electron spectrum near 413 eV, in good agreement with ab initio calculations, and we measured the corresponding Auger electron angle dependence in the molecular frame. BibTeX: @article{CryanPRL2010, author = {Cryan, James P. and Glownia, J. M. and Andreasson, J. and Belkacem, A. and Berrah, N. and Blaga, C. I. and Bostedt, C. and Bozek, J. and Buth, C. and DiMauro, L. F. and Fang, L. and Gessner, O. and Guehr, M. and Hajdu, J. and Hertlein, M. P. and Hoener, M. and Kornilov, O. and Marangos, J. P. and March, A. M. and McFarland, B. K. and Merdji, H. and Petrovic, V. S. and Raman, C. and Ray, D. and Reis, D. and Tarantelli, F. and Trigo, M. and White, J. L. and White, W. and Young, L. and Bucksbaum, P. H. and Coffee, R. N.}, title = {Auger Electron Angular Distribution of Double Core-Hole States in the Molecular Reference Frame}, journal = {Phys Rev Lett}, year = {2010}, volume = {105}, number = {8}, pages = {083004}, doi = {10.1103/PhysRevLett.105.083004} }  "Ion Pair Formation in Multiphoton Excitation of NO2 Using Linearly and Circularly Polarized Femtosecond Light Pulses: Kinetic Energy Distribution and Fragment Recoil Anisotropy"Elkharrat C, Picard YJ, Billaud P, Cornaggia C, Garzella D, Perdrix M, Houver JC, Lucchese RR and Dowek D, J Phys Chem A., Vol. 114(50), pp. 13288 - DEC 23, (2010). [BibTeX] [DOI] BibTeX: @article{ElkharratJPCA2010, author = {Elkharrat, C. and Picard, Y. J. and Billaud, P. and Cornaggia, C. and Garzella, D. and Perdrix, M. and Houver, J. C. and Lucchese, R. R. and Dowek, D.}, title = {Ion Pair Formation in Multiphoton Excitation of NO2 Using Linearly and Circularly Polarized Femtosecond Light Pulses: Kinetic Energy Distribution and Fragment Recoil Anisotropy}, journal = {J Phys Chem A}, year = {2010}, volume = {114}, number = {50}, pages = {13288}, doi = {10.1021/jp1105828} }  "Single-shot Femtosecond X-Ray Holography Using Extended References"Gauthier D, Guizar-Sicairos M, Ge X, Boutu W, Carre B, Fienup JR and Merdji H, Phys Rev Lett., Vol. 105(9), pp. 093901 - AUG 24, (2010). [Abstract] [BibTeX] [DOI] Abstract: In the context of x-ray lensless imaging, we present a recent approach for Fourier transform holography based on the use of extended references. Major advances shown here rely on a high signal efficiency and on the direct image reconstruction of the object performed by a simple linear derivative. Moreover, the extended holographic reference is easy to manufacture and can be applied to a variety of imaging experiments. Here we demonstrate single-shot imaging with a table-top, laser-based coherent soft x-ray source. A spatial resolution of 110 nm was obtained with an integration time of 20 fs. BibTeX: @article{GauthierPRL2010, author = {Gauthier, D. and Guizar-Sicairos, M. and Ge, X. and Boutu, W. and Carre, B. and Fienup, J. R. and Merdji, H.}, title = {Single-shot Femtosecond X-Ray Holography Using Extended References}, journal = {Phys Rev Lett}, year = {2010}, volume = {105}, number = {9}, pages = {093901}, doi = {10.1103/PhysRevLett.105.093901} }  "Time-resolved pump-probe experiments at the LCLS"Glownia JM, Cryan J, Andreasson J, Belkacem A, Berrah N, Blaga CI, Bostedt C, Bozek J, DiMauro LF, Fang L, Frisch J, Gessner O, Gühr M, Hajdu J, Hertlein MP, Hoener M, Huang G, Kornilov O, Marangos JP, March AM, McFarland BK, Merdji H, Petrovic VS, Raman C, Ray D, Reis DA, Trigo M, White JL, White W, Wilcox R, Young L, Coffee RN and Bucksbaum PH, Opt Express., Vol. 18(17), pp. 17620-17630. OSA - Aug, (2010). [Abstract] [BibTeX] [DOI] [URL] Abstract: The first time-resolved x-ray/optical pump-probe experiments at the SLAC Linac Coherent Light Source (LCLS) used a combination of feedback methods and post-analysis binning techniques to synchronize an ultrafast optical laser to the linac-based x-ray laser. Transient molecular nitrogen alignment revival features were resolved in time-dependent x-ray-induced fragmentation spectra. These alignment features were used to find the temporal overlap of the pump and probe pulses. The strong-field dissociation of x-ray generated quasi-bound molecular dications was used to establish the residual timing jitter. This analysis shows that the relative arrival time of the Ti:Sapphire laser and the x-ray pulses had a distribution with a standard deviation of approximately 120 fs. The largest contribution to the jitter noise spectrum was the locking of the laser oscillator to the reference RF of the accelerator, which suggests that simple technical improvements could reduce the jitter to better than 50 fs. BibTeX: @article{GlowniaOE2010, author = {James M. Glownia and J. Cryan and J. Andreasson and A. Belkacem and N. Berrah and C. I. Blaga and C. Bostedt and J. Bozek and L. F. DiMauro and L. Fang and J. Frisch and O. Gessner and M. Gühr and J. Hajdu and M. P. Hertlein and M. Hoener and G. Huang and O. Kornilov and J. P. Marangos and A. M. March and B. K. McFarland and H. Merdji and V. S. Petrovic and C. Raman and D. Ray and D. A. Reis and M. Trigo and J. L. White and W. White and R. Wilcox and L. Young and R. N. Coffee and P. H. Bucksbaum}, title = {Time-resolved pump-probe experiments at the LCLS}, journal = {Opt Express}, publisher = {OSA}, year = {2010}, volume = {18}, number = {17}, pages = {17620--17630}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-18-17-17620}, doi = {10.1364/OE.18.017620} }  "Attosecond imaging of molecular electronic wavepackets"Haessler S, Caillat J, Boutu W, Giovanetti-Teixeira C, Ruchon T, Auguste T, Diveki Z, Breger P, Maquet A, Carré B, Taïeb R and Salières P, Nat Phys., Vol. 6(3), pp. 200-206 - MARs, (2010). [Abstract] [BibTeX] [DOI] Abstract: A strong laser field may tunnel ionize a molecule from several orbitals simultaneously, forming an attosecond electron-hole wavepacket. Both temporal and spatial information on this wavepacket can be obtained through the coherent soft X-ray emission resulting from the laser-driven recollision of the liberated electron with the core. By characterizing the emission from aligned N-2 molecules, we demonstrate the attosecond contributions of the two highest occupied molecular orbitals. We determine conditions where they are disentangled in the real and imaginary parts of the emission dipole moment. This allows us to carry out a tomographic reconstruction of both orbitals with angstrom spatial resolution. Their coherent superposition provides experimental images of the attosecond wavepacket created in the ionization process. Our results open the prospect of imaging ultrafast intramolecular dynamics combining attosecond and angstrom resolutions. BibTeX: @article{HaesslerNP2010, author = {Haessler, S. and Caillat, J. and Boutu, W. and Giovanetti-Teixeira, C. and Ruchon, T. and Auguste, T. and Diveki, Z. and Breger, P. and Maquet, A. and Carré, B. and Taïeb, R. and Salières, P.}, title = {Attosecond imaging of molecular electronic wavepackets}, journal = {Nat Phys}, year = {2010}, volume = {6}, number = {3}, pages = {200-206}, doi = {10.1038/NPHYS1511} }  "Single-shot, high-dynamic-range measurement of sub-15 fs pulses by self-referenced spectral interferometry"Moulet A, Grabielle S, Cornaggia C, Forget N and Oksenhendler T, Opt Lett., Vol. 35(22), pp. 3856-3858. OSA - Nov, (2010). [Abstract] [BibTeX] [DOI] [URL] Abstract: We explore theoretically and numerically the temporal contrast limitation of a self-referenced spectral interferometry measurement. An experimental confirmation is given by characterization and fine compression of hollow-core fiber generated sub-15fs pulses, yielding an accurately measured coherent contrast of 50dB on a textpm400fs time range. BibTeX: @article{MouletOL2010, author = {A. Moulet and S. Grabielle and C. Cornaggia and N. Forget and T. Oksenhendler}, title = {Single-shot, high-dynamic-range measurement of sub-15 fs pulses by self-referenced spectral interferometry}, journal = {Opt Lett}, publisher = {OSA}, year = {2010}, volume = {35}, number = {22}, pages = {3856--3858}, url = {http://ol.osa.org/abstract.cfm?URI=ol-35-22-3856}, doi = {10.1364/OL.35.003856} }  "Spatial fingerprint of quantum path interferences in high order harmonic generation"Schapper F, Holler M, Auguste T, Zair A, Weger M, Salieres P, Gallmann L and Keller U, Opt Express., Vol. 18(3), pp. 2987-2994 - FEB 1, (2010). [Abstract] [BibTeX] Abstract: We have spatially and spectrally resolved the high order harmonic emission from an argon gas target. Under proper phase matching conditions we were able to observe for the first time the spatial fine structure originating from the interference of the two shortest quantum paths in the harmonic beam. The structure can be explained by the intensity-dependent harmonic phase of the contributions from the two paths. The spatially and spectrally resolved measurements are consistent with previous spatially integrated results. Our measurement method represents a new tool to clearly distinguish between different interference effects and to potentially observe higher order trajectories in the future with improved detection sensitivity. Here, we demonstrate additional experimental evidence that the observed interference pattern is only due to quantum-path interferences and cannot be explained by a phase modulation effect. Our experimental results are fully supported by simulations using the strong field approximation and including propagation. (C) 2010 Optical Society of America BibTeX: @article{SchapperOE2010, author = {Schapper, F. and Holler, M. and Auguste, T. and Zair, A. and Weger, M. and Salieres, P. and Gallmann, L. and Keller, U.}, title = {Spatial fingerprint of quantum path interferences in high order harmonic generation}, journal = {Opt Express}, year = {2010}, volume = {18}, number = {3}, pages = {2987-2994} }  2009 "Theoretical and experimental analysis of quantum path interferences in high-order harmonic generation"Auguste T, Salieres P, Wyatt AS, Monmayrant A, Walmsley IA, Cormier E, Zair A, Holler M, Guandalini A, Schapper F, Biegert J, Gallmann L and Keller U, Phys Rev A., Vol. 80(3), pp. 033817 - SEP, (2009). [Abstract] [BibTeX] [DOI] Abstract: We present theoretical and experimental studies on quantum path interferences in high-order harmonic generation. Simulations of the single-atom response allow us to calculate the different quantum paths contributions; their relative phases and the resulting interferences can be finely controlled through the laser intensity that provides an efficient means for controlling the electron trajectories with an accuracy on the ten attoseconds time scale. Simulations of the macroscopic response demonstrate the need of spatial and spectral filtering of the harmonic beam in order to observe the interferences between the two shortest quantum paths. Our numerical results are in very good agreement with experimental data. These investigations represent a step toward the full characterization and control of the atomic harmonic dipole. BibTeX: @article{AugustePRA2009, author = {Auguste, T. and Salieres, P. and Wyatt, A. S. and Monmayrant, A. and Walmsley, I. A. and Cormier, E. and Zair, A. and Holler, M. and Guandalini, A. and Schapper, F. and Biegert, J. and Gallmann, L. and Keller, U.}, title = {Theoretical and experimental analysis of quantum path interferences in high-order harmonic generation}, journal = {Phys Rev A}, year = {2009}, volume = {80}, number = {3}, pages = {033817}, doi = {10.1103/PhysRevA.80.033817} }  "Direct observation of quantum-path interferences in high order harmonic generation"Cormier E, Zair A, Holler M, Schapper F, Keller U, Wyatt A, Monmayrant A, Walmsley I, Auguste T and Salieres P, Eur Phys J-spec Top., Vol. 175, pp. 191-194 - AUG, (2009). [Abstract] [BibTeX] [DOI] Abstract: Intensity dependent high harmonic generation was investigated when both short and long trajectories contribute to the emission. We have directly observed for the first time clear indication of quantum-path interference through harmonic spectrum modulations. BibTeX: @article{CormierEPJST2009, author = {Cormier, E. and Zair, A. and Holler, M. and Schapper, F. and Keller, U. and Wyatt, A. and Monmayrant, A. and Walmsley, I. and Auguste, T. and Salieres, P.}, title = {Direct observation of quantum-path interferences in high order harmonic generation}, journal = {Eur Phys J-spec Top}, year = {2009}, volume = {175}, pages = {191-194}, doi = {10.1140/epjst/e2009-01140-5} }  "Ultrafast Coulomb explosion imaging of molecules"Cornaggia C, LASER PHYS., Vol. 19(8), pp. 1660-1670 - AUG, (2009). [Abstract] [BibTeX] [DOI] Abstract: Multiple ionization of small molecules leads to multifragmentation called Coulomb explosion. The atomic positions prior to the fragmentation event are determined from the multicharged fragments trajectories. Following the pioneering contribution of Prof. N.B. Delone on atomic ionization using strong laser fields, intense femtosecond laser pulses in the 10(15) W cm(-2) range permit an efficient removal of valence electrons. Pulse durations have to be reduced to a few cycles in order to avoid any significant molecular stretching during multiple ionization. Pumpprobe excitation schemes offer promising perspectives for straightforward ultrafast Coulomb explosion imaging of excited and ionized molecular species. BibTeX: @article{Cornaggia2009, author = {Cornaggia, C.}, title = {Ultrafast Coulomb explosion imaging of molecules}, journal = {LASER PHYS}, year = {2009}, volume = {19}, number = {8}, pages = {1660-1670}, doi = {10.1134/S1054660X09150122} }  "Electron-ion elastic scattering in molecules probed by laser-induced ionization"Cornaggia C, J PHYS B-AT MOL OPT., Vol. 42(16), pp. 161002 - AUG 28, (2009). [Abstract] [BibTeX] [DOI] Abstract: Electron-molecular ion elastic scattering is probed in CO2 in the 15-30 eV range using laser-induced single ionization of neutral species in the 8 x 10(13)-2 x 10(14) W cm(-2) intensity range. The experimental procedure follows the proposal of Lin and coworkers (2007 Phys. Rev. A 76 043402, 2008 New J. Phys. 10 025011) and is illustrated with atomic argon. In CO2, the angular distributions of backscattered electrons are found to depend on the collision energy as in electron-neutral molecule elastic scattering. The relatively simple experimental method may lead to time-resolved studies of structural changes in molecules with sub-femtosecond resolution. BibTeX: @article{Cornaggia2009a, author = {Cornaggia, C.}, title = {Electron-ion elastic scattering in molecules probed by laser-induced ionization}, journal = {J PHYS B-AT MOL OPT}, year = {2009}, volume = {42}, number = {16}, pages = {161002}, doi = {10.1088/0953-4075/42/16/161002} }  "Interplay between absorption, dispersion and refraction in high-order harmonic generation"Dachraoui H, Auguste T, Helmstedt A, Bartz P, Michelswirth M, Mueller N, Pfeiffer W, Salieres P and Heinzmann U, J PHYS B-AT MOL OPT., Vol. 42(17), pp. 175402 - SEP 14, (2009). [Abstract] [BibTeX] [DOI] Abstract: We report a detailed experimental and theoretical study on high-order harmonic generation of a femtosecond Ti-sapphire laser focused at an intensity of around 10(15) W cm(-2) onto a high-pressure (50-210 mbar) neon gas cell of variable length (1-3 mm). Using thorough three-dimensional simulations, we discuss the interplay between the different factors influencing the harmonic-generation efficiency, i.e. phase matching determined by the electronic and atomic dispersions, re-absorption of the harmonics by the medium and refraction of the generating laser beam. Generically, we find that, in our generation conditions, the emission yield of harmonics from the plateau region of the spectrum is absorption limited, whereas the emission from harmonics in the cut-off is strongly reduced due to both electron dispersion and ionization-induced refraction of the laser beam. A good agreement between the numerical results and the experimental data is obtained for the harmonic yield dependence on the various generation parameters (gas pressure, medium length and laser intensity). BibTeX: @article{DachraouiJPB2009, author = {Dachraoui, H. and Auguste, T. and Helmstedt, A. and Bartz, P. and Michelswirth, M. and Mueller, N. and Pfeiffer, W. and Salieres, P. and Heinzmann, U.}, title = {Interplay between absorption, dispersion and refraction in high-order harmonic generation}, journal = {J PHYS B-AT MOL OPT}, year = {2009}, volume = {42}, number = {17}, pages = {175402}, doi = {10.1088/0953-4075/42/17/175402} }  "Generation of attosecond x-ray pulses with a multicycle two-color enhanced self-amplified spontaneous emission scheme"Ding Y, Huang Z, Ratner D, Bucksbaum P and Merdji H, Phys Rev Spec Top-ac., Vol. 12(6), pp. 060703 - JUN, (2009). [Abstract] [BibTeX] [DOI] Abstract: Generation of attosecond x-ray pulses is attracting much attention within the x-ray free-electron laser (FEL) user community. Several schemes using extremely short laser pulses to manipulate the electron bunches have been proposed. In this paper, we extend the attosecond two-color enhanced self-amplified spontaneous emission scheme proposed by Zholents et al. to the long optical cycle regime using a second detuned laser and a tapered undulator. Both lasers can be about ten optical cycles long, with the second laser frequency adjustable and set to optimize the contrast between the central and side current spikes. A tapered undulator mitigates the degradation effect of the longitudinal space charge force in the undulator and suppresses the FEL gain of all side current peaks. Simulations using the Linac Coherent Light Source parameters show a single attosecond x-ray spike of similar to 100 attoseconds can be produced. The second laser can also be detuned to coherently control the number of the side x-ray spikes and the length of the radiation pulse. BibTeX: @article{DingPRSTAB2009, author = {Ding, Y. and Huang, Z. and Ratner, D. and Bucksbaum, P. and Merdji, H.}, title = {Generation of attosecond x-ray pulses with a multicycle two-color enhanced self-amplified spontaneous emission scheme}, journal = {Phys Rev Spec Top-ac}, year = {2009}, volume = {12}, number = {6}, pages = {060703}, doi = {10.1103/PhysRevSTAB.12.060703} }  "Internal frequency conversion extreme ultraviolet interferometer using mutual coherence properties of two high-order-harmonic sources"Dobosz S, Stabile H, Tortora A, Monot P, Reau F, Bougeard M, Merdji H, Carré B, Martin P, Joyeux D, Phalippou D, Delmotte F, Gautier J and Mercier R, Rev Sci Instrum., Vol. 80(11), pp. 113102 - NOV, (2009). [Abstract] [BibTeX] [DOI] Abstract: We report on an innovative two-dimensional imaging extreme ultraviolet (XUV) interferometer operating at 32 nm based on the mutual coherence of two laser high order harmonics (HOH) sources, separately generated in gas. We give the first evidence that the two mutually coherent HOH sources can be produced in two independent spatially separated gas jets, allowing for probing centimeter-sized objects. A magnification factor of 10 leads to a micron resolution associated with a subpicosecond temporal resolution. Single shot interferograms with a fringe visibility better than 30% are routinely produced. As a test of the XUV interferometer, we measure a maximum electronic density of 3 x 10(20) cm(-3) 1.1 ns after the creation of a plasma on aluminum target. (C) 2009 American Institute of Physics. [doi:10.1063/1.3257676] BibTeX: @article{DoboszRSI2009, author = {Dobosz, S. and Stabile, H. and Tortora, A. and Monot, P. and Reau, F. and Bougeard, M. and Merdji, H. and Carré, B. and Martin, Ph. and Joyeux, D. and Phalippou, D. and Delmotte, F. and Gautier, J. and Mercier, R.}, title = {Internal frequency conversion extreme ultraviolet interferometer using mutual coherence properties of two high-order-harmonic sources}, journal = {Rev Sci Instrum}, year = {2009}, volume = {80}, number = {11}, pages = {113102}, doi = {10.1063/1.3257676} }  "Attosecond chirp-encoded dynamics of light nuclei"Haessler S, Boutu W, Stankiewicz M, Frasinski LJ, Weber S, Caillat J, Taieb R, Maquet A, Breger P, Monchicourt P, Carre B and Salieres P, J PHYS B-AT MOL OPT., Vol. 42(13), pp. 134002 - JUL 14, (2009). [Abstract] [BibTeX] [DOI] Abstract: We study the spectral phase of high-order harmonic emission as an observable for probing ultrafast nuclear dynamics after the ionization of a molecule. Using a strong-field approximation theory that includes nuclear dynamics, we relate the harmonic phase to the phase of the overlap integral of the nuclear wavefunctions of the initial neutral molecule and the molecular ion after an attosecond probe delay. We determine experimentally the group delay of the high harmonic emission from D-2 and H-2 molecules, which allows us to verify the relation between harmonic frequency and the attosecond delay. The small difference in the harmonic phase between H-2 and D-2 calculated theoretically is consistent with our experimental results. BibTeX: @article{HaesslerJPB2009, author = {Haessler, S. and Boutu, W. and Stankiewicz, M. and Frasinski, L. J. and Weber, S. and Caillat, J. and Taieb, R. and Maquet, A. and Breger, P. and Monchicourt, P. and Carre, B. and Salieres, P.}, title = {Attosecond chirp-encoded dynamics of light nuclei}, journal = {J PHYS B-AT MOL OPT}, year = {2009}, volume = {42}, number = {13}, pages = {134002}, note = {International Conference on Multi-Photon Processes, Heidelberg, GERMANY, 2008}, doi = {10.1088/0953-4075/42/13/134002} }  "Phase-resolved attosecond near-threshold photoionization of molecular nitrogen"Haessler S, Fabre B, Higuet J, Caillat J, Ruchon T, Breger P, Carré B, Constant E, Maquet A, Mevel E, Salières P, Taïeb R and Mairesse Y, Phys Rev A., Vol. 80(1), pp. 011404 - JUL, (2009). [Abstract] [BibTeX] [DOI] Abstract: We photoionize nitrogen molecules with a train of extreme ultraviolet attosecond pulses together with a weak infrared field. We measure the phase of the two-color two-photon ionization transition (molecular phase) for different states of the ion. We observe a 0.9 pi shift for the electrons produced in the ionization channels leading to the X (2)Sigma(+)(g), v' = 1, and v' = 2 states. We relate this phase shift to the presence of a complex resonance in the continuum. By providing both a high spectral and temporal resolution, this general approach gives access to the evolution of extremely short-lived states, which is often not accessible otherwise. BibTeX: @article{HaesslerPRA2009, author = {Haessler, S. and Fabre, B. and Higuet, J. and Caillat, J. and Ruchon, T. and Breger, P. and Carré, B. and Constant, E. and Maquet, A. and Mevel, E. and Salières, P. and Taïeb, R. and Mairesse, Y.}, title = {Phase-resolved attosecond near-threshold photoionization of molecular nitrogen}, journal = {Phys Rev A}, year = {2009}, volume = {80}, number = {1}, pages = {011404}, doi = {10.1103/PhysRevA.80.011404} }  "Ionization effects on spectral signatures of quantum-path interference in high-harmonic generation"Holler M, Zaïr A, Schapper F, Auguste T, Cormier E, Wyatt A, Monmayrant A, Walmsley IA, Gallmann L, Salières P and Keller U, Opt Express., Vol. 17(7), pp. 5716-5722. OSA - Mars, (2009). [Abstract] [BibTeX] [DOI] [URL] Abstract: The interference between the emission originating from the short and long electron quantum paths is intrinsic to the high harmonic generation process. We investigate the universal properties of these quantum-path interferences in various generation media and discuss how ionization effects influence the observed interference structures. Our comparison of quantum-path interferences observed in xenon, argon, and neon demonstrates that our experimental tools are generally applicable and should also allow investigating more complex systems such as molecules or clusters. BibTeX: @article{HollerOE2009, author = {M. Holler and A. Zaïr and F. Schapper and T. Auguste and E. Cormier and A. Wyatt and A. Monmayrant and I. A. Walmsley and L. Gallmann and P. Salières and U. Keller}, title = {Ionization effects on spectral signatures of quantum-path interference in high-harmonic generation}, journal = {Opt Express}, publisher = {OSA}, year = {2009}, volume = {17}, number = {7}, pages = {5716--5722}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-17-7-5716}, doi = {10.1364/OE.17.005716} }  "Exciton-exciton interactions in CdWO4 irradiated by intense femtosecond vacuum ultraviolet pulses"Kirm M, Nagirnyi V, Feldbach E, De Grazia M, Carré B, Merdji H, Guizard S, Geoffroy G, Gaudin J, Fedorov N, Martin P, Vasil'ev A and Belsky A, Phys Rev B., Vol. 79(23), pp. 233103 - JUN, (2009). [Abstract] [BibTeX] [DOI] Abstract: Exciton-exciton interaction is experimentally revealed and quantitatively analyzed in a wide band-gap scintillator material CdWO4. Under high-intensity femtosecond vacuum ultraviolet excitation, the CdWO4 luminescence is quenched, while its decay becomes essentially nonexponential. We propose an analytical model, which successfully reproduces the decay kinetics recorded in a wide range of excitation densities. The dipole-dipole interaction between excitons leading to their nonradiative decay is shown to be the main cause of a nonproportional response common for many scintillators. BibTeX: @article{KirmPRB2009, author = {Kirm, M. and Nagirnyi, V. and Feldbach, E. and De Grazia, M. and Carré, B. and Merdji, H. and Guizard, S. and Geoffroy, G. and Gaudin, J. and Fedorov, N. and Martin, P. and Vasil'ev, A. and Belsky, A.}, title = {Exciton-exciton interactions in CdWO4 irradiated by intense femtosecond vacuum ultraviolet pulses}, journal = {Phys Rev B}, year = {2009}, volume = {79}, number = {23}, pages = {233103}, doi = {10.1103/PhysRevB.79.233103} }  "Surface modification of polymethylmethacrylate irradiated with 60 fs single laser pulses"Klinger D, Sobierajski R, Nietubyc R, Krzywinski J, Pelka J, Juha L, Jurek M, Zymierska D, Guizard S and Merdji H, Radiat Phys Chem., Vol. 78(Suppl. 10), pp. S71-S74 - OCT, (2009). [Abstract] [BibTeX] [DOI] Abstract: An ablation by a femtosecond laser pulses of poly methyl methacrylate was investigated in the near-infrared region. The morphological changes due to increasing laser fluency were examined. The size and shape as well as morphological forms occurring in the resulted craters were analyzed as a function of irradiation fluency. Various forms of surface modifications in ablated crater i.e. cracks and smaller features like honey-comb-like structures, and ripples with an average period of 800 nm were observed. The threshold fluency for observable changes of the sample surface, the ablation threshold and the threshold fluency for creation of the structure in the centre of the cavity were determined for 60 fs laser pulse. Obtained data were compared with available literature data. (C) 2009 Published by Elsevier Ltd. BibTeX: @article{KlingerRPC2009, author = {Klinger, D. and Sobierajski, R. and Nietubyc, R. and Krzywinski, J. and Pelka, J. and Juha, L. and Jurek, M. and Zymierska, D. and Guizard, S. and Merdji, H.}, title = {Surface modification of polymethylmethacrylate irradiated with 60 fs single laser pulses}, journal = {Radiat Phys Chem}, year = {2009}, volume = {78}, number = {Suppl. 10}, pages = {S71-S74}, note = {9th International School and Symposium on Synchrotron Radiation in Natural Science (ISSRNS-9), Ameliowka, POLAND, JUN 15-20, 2008}, doi = {10.1016/j.radphyschem.2009.04.031} }  "Seed level requirement for improving the temporal coherence of a Free-Electron Laser"Lambert G, Hara T, Labat M, Tanikawa T, Tanaka Y, Yabashi M, Garzella D, Carré B and Couprie ME, Epl-europhys Lett., Vol. 88(5), pp. 54002 - DEC, (2009). [Abstract] [BibTeX] [DOI] Abstract: The temporal coherence of Free-Electron Laser (FEL) sources, which exhibit, in the self-amplified spontaneous-emission mode, spiking spectral and temporal distributions, can be drastically improved by seeding with an external laser or high-order harmonics. Here, experiments at 160 nm put in evidence that the improvement of spectral properties (and thus temporal coherence) of the FEL radiation takes place for a larger seed intensity than the one required to overcome the shot noise. Copyright (C) EPLA, 2009 BibTeX: @article{LambertEPL2009, author = {Lambert, G. and Hara, T. and Labat, M. and Tanikawa, T. and Tanaka, Y. and Yabashi, M. and Garzella, D. and Carré, B. and Couprie, M. E.}, title = {Seed level requirement for improving the temporal coherence of a Free-Electron Laser}, journal = {Epl-europhys Lett}, year = {2009}, volume = {88}, number = {5}, pages = {54002}, doi = {10.1209/0295-5075/88/54002} }  "Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source"Ravasio A, Gauthier D, Maia FRNC, Billon M, Caumes J-P, Garzella D, Geleoc M, Gobert O, Hergott J-F, Pena A-M, Perez H, Carré B, Bourhis E, Gierak J, Madouri A, Mailly D, Schiedt B, Fajardo M, Gautier J, Zeitoun P, Bucksbaum PH, Hajdu J and Merdji H, Phys Rev Lett., Vol. 103(2), pp. 028104 - JUL 10, (2009). [Abstract] [BibTeX] [DOI] Abstract: Coherent x-ray diffractive imaging is a powerful method for studies on nonperiodic structures on the nanoscale. Access to femtosecond dynamics in major physical, chemical, and biological processes requires single-shot diffraction data. Up to now, this has been limited to intense coherent pulses from a free electron laser. Here we show that laser-driven ultrashort x-ray sources offer a comparatively inexpensive alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20 fs pulse from a table-top high-harmonic x-ray laser. Images were reconstructed with a resolution of 119 nm from the single shot and 62 nm from multiple shots. BibTeX: @article{RavasioPRL2009, author = {Ravasio, A. and Gauthier, D. and Maia, F. R. N. C. and Billon, M. and Caumes, J-P. and Garzella, D. and Geleoc, M. and Gobert, O. and Hergott, J-F. and Pena, A-M. and Perez, H. and Carré, B. and Bourhis, E. and Gierak, J. and Madouri, A. and Mailly, D. and Schiedt, B. and Fajardo, M. and Gautier, J. and Zeitoun, P. and Bucksbaum, P. H. and Hajdu, J. and Merdji, H.}, title = {Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source}, journal = {Phys Rev Lett}, year = {2009}, volume = {103}, number = {2}, pages = {028104}, doi = {10.1103/PhysRevLett.103.028104} }  "Femtosecond isomerization dynamics in the ethylene cation measured in an EUV-pump NIR-probe configuration"van Tilborg J, Allison TK, Wright TW, Hertlein MP, Falcone RW, Liu Y, Merdji H and Belkacem A, J PHYS B-AT MOL OPT., Vol. 42(8), pp. 081002 - APR 28, (2009). [Abstract] [BibTeX] [DOI] Abstract: Dynamics in the excited ethylene cation C2H4+ lead to isomerization to the ethylidene configuration (HC-CH3)(+), which is predicted to be a transient configuration for electronic relaxation. With an intense femtosecond extreme ultraviolet pump pulse to populate the excited state, and a near infrared probe pulse to produce the fragments CH+ and CH3+ (which provides a direct signature of ethylidene), we measure optimum fragment yields at a probe delay of 80 fs. Also, an H-2-stretch transient configuration, yielding H-2(+) upon probing, is found to succeed the ethylidene configuration. We find that a simple single- or double-decay model does not match the data, and we present a modified model (introduction of an isomerization delay of 50 +/- 25 fs) that does provide agreement. BibTeX: @article{VanTilborgJPB2009, author = {van Tilborg, J. and Allison, T. K. and Wright, T. W. and Hertlein, M. P. and Falcone, R. W. and Liu, Y. and Merdji, H. and Belkacem, A.}, title = {Femtosecond isomerization dynamics in the ethylene cation measured in an EUV-pump NIR-probe configuration}, journal = {J PHYS B-AT MOL OPT}, year = {2009}, volume = {42}, number = {8}, pages = {081002}, doi = {10.1088/0953-4075/42/8/081002} }  2008 "Numerical study on high-order harmonic generation by a Bessel-Gauss laser beam"Auguste T, Gobert O and Carré B, Phys Rev A., Vol. 78(3), pp. 033411 - SEP, (2008). [Abstract] [BibTeX] [DOI] Abstract: We present a theoretical study of high-order harmonic generation by a Bessel-Gauss laser beam focused in a low-density gas medium. We consider in detail the generation of the 21st-order harmonic of a short-pulse Ti:sapphire laser in an argon gas jet. Within the strong-field approximation for the atomic dipole, and a complete account of the macroscopic propagation, we compute the number of photons produced and the brightness as a function of the medium parameters and the focusing conditions. We show that emission of the 21st-order harmonic can be maximized by adjusting the half-angle of the Bessel-Gauss beam. We find that, at given intensity and confocal parameter, the conversion efficiency is significantly enhanced with a Bessel-Gauss beam, as compared with a Gaussian one. Of particular interest for many applications, we also observe a spectacular increase of the brightness, by two decades, at maximum emission. BibTeX: @article{AugustePRA2008, author = {Auguste, T. and Gobert, O. and Carré, B.}, title = {Numerical study on high-order harmonic generation by a Bessel-Gauss laser beam}, journal = {Phys Rev A}, year = {2008}, volume = {78}, number = {3}, pages = {033411}, doi = {10.1103/PhysRevA.78.033411} }  "Coherent control of attosecond emission from aligned molecules"Boutu W, Haessler S, Merdji H, Breger P, Waters G, Stankiewicz M, Frasinski LJ, Taieb R, Caillat J, Maquet A, Monchicourt P, Carre B and Salieres P, Nat Phys., Vol. 4(7), pp. 545-549 - JUL, (2008). [Abstract] [BibTeX] [DOI] Abstract: Controlling attosecond electron wave packets and soft X-ray pulses represents a formidable challenge of general implication to many areas of science(1-4). A strong laser field interacting with atoms or molecules drives ultrafast intra-atomic/molecular electron wave packets on a subfemtosecond timescale, resulting in the emission of attosecond bursts of extreme-ultraviolet light(5,6). Controlling the intra-atomic/molecular electron dynamics enables steering of the attosecond emission(7,8). Here, we carry out a coherent control in linear molecules, where the interaction of the laser-driven electron wave packet with the core leads to quantum interferences(9-12). We demonstrate that these interferences can be finely controlled by turning the molecular axis relative to the laser polarization, that is, changing the electron recollision angle. The wave-packet coulombic distortion modifies the spectral phase jump measured in the extreme-ultraviolet emission. Our attosecond control of the interference results in attosecond pulse shaping, useful for future applications in ultrafast coherent control of atomic and molecular processes. BibTeX: @article{BoutuNP2008, author = {Boutu, W. and Haessler, S. and Merdji, H. and Breger, P. and Waters, G. and Stankiewicz, M. and Frasinski, L. J. and Taieb, R. and Caillat, J. and Maquet, A. and Monchicourt, P. and Carre, B. and Salieres, P.}, title = {Coherent control of attosecond emission from aligned molecules}, journal = {Nat Phys}, year = {2008}, volume = {4}, number = {7}, pages = {545-549}, doi = {10.1038/nphys964} }  "Time-dependent FEL wavefront propagation calculations: Fourier optics approach"Chubar O, Couprie M-E, Labat M, Lambert G, Polack F and Tcherbakoff O, NUCL INSTRUM METH A., Vol. 593, pp. 30-34 - August, (2008). [BibTeX] [DOI] BibTeX: @article{ChubarNIMPR2008, author = {Chubar, O. and Couprie, M.-E. and Labat, M. and Lambert, G. and Polack, F. and Tcherbakoff, O.}, title = {Time-dependent FEL wavefront propagation calculations: Fourier optics approach}, journal = {NUCL INSTRUM METH A}, year = {2008}, volume = {593}, pages = {30-34}, doi = {10.1016/j.nima.2008.04.058} }  "Molecular rescattering signature in above-threshold ionization"Cornaggia C, Phys Rev A., Vol. 78(4), pp. 041401 - OCT, (2008). [Abstract] [BibTeX] [DOI] Abstract: Above-threshold ionization electron spectra recorded with nonaligned molecules such as N-2, CO2, and C3H4 exhibit the same classical kinematics features of electrons in strong laser fields as for atoms in the 10(14) W cm(-2) laser intensity range. The cutoff energies for direct and rescattered electrons are governed by the electron classical dynamics in the intense laser field. The main differences are found in the energy-resolved angular distributions. The molecular potential leads to a larger differential elastic cross section for forward-rescattered electrons and as a consequence to broader angular distributions for rescattered electrons with energies lower than 5U(p), where U-p is the ponderomotive potential. BibTeX: @article{CornaggiaPRA2008, author = {Cornaggia, C.}, title = {Molecular rescattering signature in above-threshold ionization}, journal = {Phys Rev A}, year = {2008}, volume = {78}, number = {4}, pages = {041401}, doi = {10.1103/PhysRevA.78.041401} }  "Optimization of the wave front of high order harmonics"Gautier J, Zeitoun P, Hauri C, Morlens AS, Rey G, Valentin C, Papalarazou E, Goddet JP, Sebban S, Burgy F, Mercere P, Idir M, Dovillaire G, Levecq X, Bucourt S, Fajardo M, Merdji H and Caumes JP, EUR PHYS J D., Vol. 48(3), pp. 459-463 - JUL, (2008). [Abstract] [BibTeX] [DOI] Abstract: We present a full optimization of the high harmonics wave front owing to the use of a soft X-ray Hartmann sensor. The sensor was calibrated using a high harmonic source with an accuracy of lambda/50 root-mean-square (rms) with lambda around 30 nm. We observed a high harmonic wave front of lambda/7 rms, which is two times the diffraction-limit, astigmatism being the dominant aberration for every condition of generation. By clipping slightly the unfocused high harmonic beam, it is possible to produce a diffraction-limited beam containing approximately 90% of the incident energy. BibTeX: @article{GautierEPJD2008, author = {Gautier, J. and Zeitoun, P. and Hauri, C. and Morlens, A. -S. and Rey, G. and Valentin, C. and Papalarazou, E. and Goddet, J. -P. and Sebban, S. and Burgy, F. and Mercere, P. and Idir, M. and Dovillaire, G. and Levecq, X. and Bucourt, S. and Fajardo, M. and Merdji, H. and Caumes, J. -P.}, title = {Optimization of the wave front of high order harmonics}, journal = {EUR PHYS J D}, year = {2008}, volume = {48}, number = {3}, pages = {459-463}, doi = {10.1140/epjd/e2008-00123-2} }  "Seeding experiments at SPARC"Giannessi L, Alesini D, Biagini M, Boscolo M, Bougeard M, Bre'ger P, Carré B, Castellano M, Cianchi A, Ciocci F, Chiadroni E, Clozza A, Couprie ME, Cultrera L, Dattoli G, De Silvestri S, Di Pace A, Di Pirro G, Doria A, Drago A, Ferrario M, Filippetto D, Frassetto F, Fusco V, Gallerano GP, Gallo A, Garzella D, Ghigo A, Germano M, Giovenale E, Labat M, Lambert G, Mattioli M, Merdji H, Monchicourt P, Migliorati M, Musumeci P, Nisoli M, Orlandi GL, Ottaviani PL, Pace E, Pagnutti S, Palumbo L, Petralia A, Petrarca M, Poletto L, Quattromini M, Reiche S, Rosenzweig JB, Ronsivalle C, Salières P, Sabia E, Sansone G, Serafini L, Spassovsky I, Spataro B, Stagira S, Surrenti V, Tchebakoff O, Tomassini S, Tondello G, Vaccarezza C and Vicario C, NUCL INSTRUM METH A., Vol. 593(1-2), pp. 132-136 - AUG 1, (2008). [Abstract] [BibTeX] [DOI] Abstract: In the framework of the DS4 EUROFEL collaboration, a research work plan at the SPARC free-electron laser (FEL) test facility aiming at the investigation of seeded and cascaded FEL configurations is under implementation. The main goal of the collaboration is to study and test the amplification and the FEL harmonic generation process of an input seed signal obtained as higher-order harmonics generated both in crystals (400 and 266 nm) and in gases (266,160,114 nm). The SPARC FEL can be configured to test several cascaded FEL configurations. In this paper we introduce SPARC and its main parameters and we analyze the superradiant cascade and the harmonic cascade seeded with a signal with the typical time structure of the harmonics generated in gas. (C) 2008 Elsevier B.V. All rights reserved. BibTeX: @article{GiannessiNIMPR2008, author = {Giannessi, L. and Alesini, D. and Biagini, M. and Boscolo, M. and Bougeard, M. and Br P. and Carré, B. and Castellano, M. and Cianchi, A. and Ciocci, F. and Chiadroni, E. and Clozza, A. and Couprie, M. E. and Cultrera, L. and Dattoli, G. and De Silvestri, S. and Di Pace, A. and Di Pirro, G. and Doria, A. and Drago, A. and Ferrario, M. and Filippetto, D. and Frassetto, F. and Fusco, V. and Gallerano, G. P. and Gallo, A. and Garzella, D. and Ghigo, A. and Germano, M. and Giovenale, E. and Labat, M. and Lambert, G. and Mattioli, M. and Merdji, H. and Monchicourt, P. and Migliorati, M. and Musumeci, P. and Nisoli, M. and Orlandi, G. L. and Ottaviani, P. L. and Pace, E. and Pagnutti, S. and Palumbo, L. and Petralia, A. and Petrarca, M. and Poletto, L. and Quattromini, M. and Reiche, S. and Rosenzweig, J. B. and Ronsivalle, C. and Salières, P. and Sabia, E. and Sansone, G. and Serafini, L. and Spassovsky, I. and Spataro, B. and Stagira, S. and Surrenti, V. and Tchebakoff, O. and Tomassini, S. and Tondello, G. and Vaccarezza, C. and Vicario, C.}, title = {Seeding experiments at SPARC}, journal = {NUCL INSTRUM METH A}, year = {2008}, volume = {593}, number = {1-2}, pages = {132-136}, note = {International Workshop on Frontiers in FEL Physics and Related Topics, Tuscany, ITALY, SEP 08-14, 2007}, doi = {10.1016/j.nima.2008.04.073} }  "Complete momentum analysis of multi-photon photo-double ionization of xenon by XUV and infrared photons"Guyétand O, Gisselbrecht M, Huetz A, Agostini P, Carré B, Breger P, Gobert O, Garzella D, Hergott J-F, Tcherbakoff O, Merdji H, Bougeard M, Rottke H, Böttcher M, Ansari Z, Antoine P and DiMauro LF, J PHYS B-AT MOL OPT. Vol. 41(6), pp. 065601 - (2008). [Abstract] [BibTeX] [URL] Abstract: Photo-double ionization (PDI) of xenon by the Ti:Sapphire laser fundamental frequency combined to its 19th and 25th harmonics has been studied by means of a momentum imaging spectrometer. The measurement of the two emitted photoelectrons' momenta and their energy and angular correlations gives insight into the various mechanisms leading to PDI. Although the conditions for non-sequential direct photo-double ionization are fulfilled in the experiment, it is found that the two-step processes dominate. BibTeX: @article{GuyetandJPB2008b, author = {O Guyétand and M Gisselbrecht and A Huetz and P Agostini and B Carré and P Breger and O Gobert and D Garzella and J-F Hergott and O Tcherbakoff and H Merdji and M Bougeard and H Rottke and M Böttcher and Z Ansari and P Antoine and L F DiMauro}, title = {Complete momentum analysis of multi-photon photo-double ionization of xenon by XUV and infrared photons}, journal = {J PHYS B-AT MOL OPT}, year = {2008}, volume = {41}, number = {6}, pages = {065601}, url = {http://stacks.iop.org/0953-4075/41/065601} }  "Evolution of angular distributions in two-colour, few-photon ionization of helium"Guyétand O, Gisselbrecht M, Huetz A, Agostini P, Taïeb R, Maquet A, Carré B, Breger P, Gobert O, Garzella D, Hergott J-F, Tcherbakoff O, Merdji H, Bougeard M, Rottke H, Böttcher M, Ansari Z and Antoine P, J PHYS B-AT MOL OPT. Vol. 41(5), pp. 051002 (6pp) - (2008). [Abstract] [BibTeX] [URL] Abstract: Single ionization of helium by a superposition of selected XUV high harmonics and infrared radiation has been studied by a momentum imaging technique. The measured angular distributions of photoelectrons are compared to numerical time-dependent calculations, showing very good agreement after average. The calculated angular distributions appear to depend critically on the delay between harmonic and infrared pulses on the attosecond scale, and on the relative phases and intensities of the harmonics. BibTeX: @article{Guyetand2008, author = {O Guyétand and M Gisselbrecht and A Huetz and P Agostini and R Taïeb and A Maquet and B Carré and P Breger and O Gobert and D Garzella and J-F Hergott and O Tcherbakoff and H Merdji and M Bougeard and H Rottke and M Böttcher and Z Ansari and P Antoine}, title = {Evolution of angular distributions in two-colour, few-photon ionization of helium}, journal = {J PHYS B-AT MOL OPT}, year = {2008}, volume = {41}, number = {5}, pages = {051002 (6pp)}, url = {http://stacks.iop.org/0953-4075/41/051002} }  "Behaviour of scintillators under XUV free electron laser radiation"Kirm M, Babin V, Feldbach E, Guizard S, De Grazia M, Nagirnyi V, Vasil'ev A and Vielhauer S, J Lumin., In Proceedings of the 16th International Conference on Dynamical Processes in Excited States of Solids, 16th International Conference on Dynamical Processes in Excited States of Solids. Vol. 128(5-6), pp. 732-734 - (2008). [Abstract] [BibTeX] [URL] Abstract: Free electron lasers (FEL) are new generation accelerator-based short wavelength light sources providing high pulse intensity and femtosecond pulse duration, which enable investigation of interaction of elementary excitations in solids under extreme conditions. Using the FLASH facility of HASYLAB at DESY (Hamburg, Germany), we investigated the response of different materials with scintillating properties based on intrinsic emissions to the 25.6 and 13.8 nm FEL radiation by means of time-resolved luminescence spectroscopy. FLASH delivered single pulses of 25 fs duration having energy per pulse up to 30 [mu]J resulting in power densities of ~1012 W/cm2 on crystals. As a function of excitation density we observed the shortening of lifetime and non-exponential behaviour of emission decays in CaWO4, while the emission spectra recorded are comparable to those obtained at conventional excitation sources. BibTeX: @article{KirmJL2008, author = {Kirm, M. and Babin, V. and Feldbach, E. and Guizard, S. and De Grazia, M. and Nagirnyi, V. and Vasil'ev, A. and Vielhauer, S.}, title = {Behaviour of scintillators under XUV free electron laser radiation}, booktitle = {Proceedings of the 16th International Conference on Dynamical Processes in Excited States of Solids, 16th International Conference on Dynamical Processes in Excited States of Solids}, journal = {J Lumin}, year = {2008}, volume = {128}, number = {5-6}, pages = {732--734}, url = {http://www.sciencedirect.com/science/article/B6TJH-4R3C0JJ-2/1/3276821122002f08766fce41b71fb975} }  "Local heating induced by Coherent Harmonic Generation on electron beam dynamics in storage ring"Labat M, Bruni C, Lambert G, Hosaka M, Shimada M, Katoh M, Mochihashi A, Takashima Y, Hara T and Couprie M-E, Epl-europhys Lett. Vol. 81(3), pp. 34004 - (2008). [BibTeX] [DOI] BibTeX: @article{LabatEPL2008, author = {Labat, M. and Bruni, C. and Lambert, G. and Hosaka, M. and Shimada, M. and Katoh, M. and Mochihashi, A. and Takashima, Y. and Hara, T. and Couprie, M.-E.}, title = {Local heating induced by Coherent Harmonic Generation on electron beam dynamics in storage ring}, journal = {Epl-europhys Lett}, year = {2008}, volume = {81}, number = {3}, pages = {34004}, doi = {10.1209/0295-5075/81/34004} }  "Coherent Harmonic Generation experiments on UVSOR-II storage ring"Labat M, Lambert G, Couprie M, Shimada M, Katoh M, Hosaka M, Takashima Y, Hara T and Mochihashi A, NUCL INSTRUM METH A. Vol. 593(1-2), pp. 1 - 5 (2008). [BibTeX] [DOI] [URL] BibTeX: @article{LabatNIMPR2008, author = {M. Labat and G. Lambert and M.E. Couprie and M. Shimada and M. Katoh and M. Hosaka and Y. Takashima and T. Hara and A. Mochihashi}, title = {Coherent Harmonic Generation experiments on UVSOR-II storage ring}, journal = {NUCL INSTRUM METH A}, year = {2008}, volume = {593}, number = {1-2}, pages = {1 - 5}, note = {FEL Fronties 2007 Proceedings of the International Workshop on Frontiers in FEL Physics and Related Topics}, url = {http://www.sciencedirect.com/science/article/pii/S0168900208006049}, doi = {10.1016/j.nima.2008.04.042} }  "Test of HHG chambers for seeding at SPARC"Labat M, Tcherbakoff O, Lambert G, Garzella D, Carré B and Couprie ME, NUCL INSTRUM METH A., Vol. 593(1-2), pp. 26-29 - AUG 1, (2008). [Abstract] [BibTeX] [DOI] Abstract: We propose to use High Order Harmonic Generation (HHG) in gases to seed the SPARC FEL (Frascati, Italy) in the high gain harmonic generation configuration. HHG produces a coherent XUV source by focussing an intense laser pulse into a gas medium. This output radiation is composed of fundamental and odd harmonics of the laser. Dedicated chambers have been realized and tested at the CEA (Saclay, France). They allow generation and shaping of the harmonic beam for further focussing at variable position. A final periscope will allow the injection of the selected harmonics inside the first section of the undulator. The SPARC facility will deliver an electron beam at 200MeV, passing through a six sections long undulator. Injection of the third and fifth harmonics (266 and 114 nm) is foreseen. Nonlinear harmonics could enable to reach 32 mm. In this paper, we present the tests performed on the seeding chambers, as well as simulations of the expected performances of the HHG seeded FEL. (c) 2008 Elsevier B.V. All rights reserved. BibTeX: @article{LabatNIMPR2008b, author = {Labat, M. and Tcherbakoff, O. and Lambert, G. and Garzella, D. and Carré, B. and Couprie, M. E.}, title = {Test of HHG chambers for seeding at SPARC}, journal = {NUCL INSTRUM METH A}, year = {2008}, volume = {593}, number = {1-2}, pages = {26-29}, note = {International Workshop on Frontiers in FEL Physics and Related Topics, Tuscany, ITALY, SEP 08-14, 2007}, doi = {10.1016/j.nima.2008.04.043} }  "Injection of harmonics generated in gas in a free-electron laser providing intense and coherent extreme-ultraviolet light",Lambert G, Hara T, Garzella D, Tanikawa T, Labat M, Carré B, Kitamura H, Shintake T, Bougeard M, Inoue S, Tanaka Y, Salières P, Merdji H, Chubar O, Gobert O, Tahara K and Couprie ME, Nat Phys., Vol. 4(4), pp. 296-300 - APR, (2008). [Abstract] [BibTeX] [DOI] Abstract: Conventional synchrotron radiation sources enable the structure of matter to be studied at near-atomic spatial resolution and picosecond temporal resolution. Free-electron lasers promise to extend this down to femtosecond timescales. The process by which free-electron lasers amplify synchrotron light-known as self-amplified spontaneous emission(1-3) - is only partially temporally coherent, but this can be improved by seeding it with an external laser(4,5). Here we explore the use of seed light produced by high-order harmonic generation in a gas(6-9), covering wavelengths from the ultraviolet to soft X-rays. Using the SPring-8 Compact SASE Source test accelerator(10-12), we demonstrate an increase of three orders of magnitude in the intensity of the fundamental radiation at 160 nm, halving of the free-electron laser saturation length, and the generation of nonlinear harmonics(13) at 54 nm and 32 nm. The low seed level used in this demonstration suggests that nonlinear harmonic schemes should enable the generation of fully coherent soft X-rays at wavelengths down to the so-called water window', vital for the study of biological samples. BibTeX: @article{LambertNP2008, author = {Lambert, G. and Hara, T. and Garzella, D. and Tanikawa, T. and Labat, M. and Carré, B. and Kitamura, H. and Shintake, T. and Bougeard, M. and Inoue, S. and Tanaka, Y. and Salières, P. and Merdji, H. and Chubar, O. and Gobert, O. and Tahara, K. and Couprie, M. -E.}, title = {Injection of harmonics generated in gas in a free-electron laser providing intense and coherent extreme-ultraviolet light}, journal = {Nat Phys}, year = {2008}, volume = {4}, number = {4}, pages = {296-300}, doi = {10.1038/nphys889} }  "Polarization-resolved pump-probe spectroscopy with high harmonics"Mairesse Y, Haessler S, Fabre B, Higuet J, Boutu W, Breger P, Constant E, Descamps D, Mével E, Petit S and Salières P, New J Phys. Vol. 10(2), pp. 025028 (11pp) - (2008). [Abstract] [BibTeX] [URL] Abstract: High harmonic generation in gases can be used as a probe of the electronic structure of the emitting medium, with attosecond temporal resolution and angström spatial resolution. The prospect of measuring molecular dynamics by pump-probe spectroscopy with such precision is attracting a lot of interest. An important issue in pump-probe spectroscopy lies in the ability to detect small signals: the detected signal can be easily dominated by the contributions from non-excited molecules or from a carrier gas. In this paper, we demonstrate that polarization-resolved pump-probe spectroscopy can be used to overcome this issue. We study high harmonic generation from rotationally excited molecules. We show that by measuring the harmonic field that is generated orthogonally to the driving laser field, the contrast in the detection of alignment revivals in nitrogen can be increased by a factor 4. We use this configuration to measure alignment revivals in an argon-nitrogen mixture, in which the total harmonic signal is dominated by the contributions from argon. BibTeX: @article{MairesseNJP2008, author = {Y Mairesse and S Haessler and B Fabre and J Higuet and W Boutu and P Breger and E Constant and D Descamps and E Mével and S Petit and P Salières}, title = {Polarization-resolved pump-probe spectroscopy with high harmonics}, journal = {New J Phys}, year = {2008}, volume = {10}, number = {2}, pages = {025028 (11pp)}, url = {http://stacks.iop.org/1367-2630/10/025028} }  "Coherent Electron Scattering Captured by an Attosecond Quantum Stroboscope"Mauritsson J, Johnsson P, Mansten E, Swoboda M, Ruchon T, L'Huillier A and Schafer KJ, Phys Rev Lett. Vol. 100(7), pp. 073003. APS - (2008). [BibTeX] [DOI] [URL] BibTeX: @article{MauritssonPRL2008, author = {J. Mauritsson and P. Johnsson and E. Mansten and M. Swoboda and T. Ruchon and A. L'Huillier and K. J. Schafer}, title = {Coherent Electron Scattering Captured by an Attosecond Quantum Stroboscope}, journal = {Phys Rev Lett}, publisher = {APS}, year = {2008}, volume = {100}, number = {7}, pages = {073003}, url = {http://link.aps.org/abstract/PRL/v100/e073003}, doi = {10.1103/PhysRevLett.100.073003} }  "Laser-Intensity Dependent Vibrational Excitation and Alignment of Molecular Ions in the Ultrafast Multiphoton Regime"Posthumus J, Fabre B, Cornaggia C, de Ruette N and Urbain X, Phys Rev Lett., Vol. 101, pp. 233004. American Physical Society - Dec, (2008). [BibTeX] [DOI] [URL] BibTeX: @article{PosthumusPRL2008, author = {Posthumus, J.H. and Fabre, B. and Cornaggia, C. and de Ruette, N. and Urbain, X.}, title = {Laser-Intensity Dependent Vibrational Excitation and Alignment of Molecular Ions in the Ultrafast Multiphoton Regime}, journal = {Phys Rev Lett}, publisher = {American Physical Society}, year = {2008}, volume = {101}, pages = {233004}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.101.233004}, doi = {10.1103/PhysRevLett.101.233004} }  "Photoionization in combined ultra short XUV and infrared laser pulses"Rottke H, Guyétand O, Gisselbrecht M, Huetz A, Agostini P, Carré B, Breger P, Gobert O, Garzella D, Hergott J-F, Tcherbakor O, Merdji H, Bougeard M, Böttcher M, Zhavoronkov N, Ansari Z, Sandner W, Antoine P and DiMauro LF, Journal of Physics: Conference Series. Vol. 141(1), pp. 012015 - (2008). [Abstract] [BibTeX] [URL] Abstract: Multi-photon-double ionization of xenon by Ti:Sapphire laser pulses combined with their 25th harmonic has been studied by means of a momentum imaging spectrometer. The determination of the momenta of the emitted photoelectron pair and of its energy and angular correlation gives insight into the various mechanisms leading to double ionization. Although the conditions for non sequential direct multi-photon double ionization are met in the experiment, it is found that two-step sequential processes prevail. BibTeX: @article{RottkeJP2008, author = {H Rottke and O Guyétand and M Gisselbrecht and A Huetz and P Agostini and B Carré and P Breger and O Gobert and D Garzella and J-F Hergott and O Tcherbakor and H Merdji and M Bougeard and M Böttcher and N Zhavoronkov and Z Ansari and W Sandner and P Antoine and L F DiMauro}, title = {Photoionization in combined ultra short XUV and infrared laser pulses}, journal = {Journal of Physics: Conference Series}, year = {2008}, volume = {141}, number = {1}, pages = {012015}, url = {http://stacks.iop.org/1742-6596/141/i=1/a=012015} }  "Macroscopic effects in attosecond pulse generation"Ruchon T, Hauri CP, Varjú K, Mansten E, Swoboda M, Lopez-Martens R and L'Huillier A, New J Phys. Vol. 10(2), pp. 025027 - (2008). [Abstract] [BibTeX] [URL] Abstract: We examine how the generation and propagation of high-order harmonics in a partly ionized gas medium affect their strength and synchronization. The temporal properties of the resulting attosecond pulses generated in long gas targets can be significantly influenced by macroscopic effects, in particular by the intensity in the medium and the degree of ionization which control the dispersion. Under some conditions, the use of gas targets longer than the absorption length can lead to the generation of compressed attosecond pulses. We show these macroscopic effects experimentally, using a 6 mm-long argon-filled gas cell as the generating medium. BibTeX: @article{RuchonNJP2008, author = {T Ruchon and C P Hauri and K Varjú and E Mansten and M Swoboda and R Lopez-Martens and A L'Huillier}, title = {Macroscopic effects in attosecond pulse generation}, journal = {New J Phys}, year = {2008}, volume = {10}, number = {2}, pages = {025027}, url = {http://stacks.iop.org/1367-2630/10/025027} }  "H-2 double ionization with few-cycle laser pulses"Saugout S, Charron E and Cornaggia C, Phys Rev A., Vol. 77(2), pp. 023404 - FEB, (2008). [Abstract] [BibTeX] [DOI] Abstract: The temporal dynamics of double ionization of H-2 has been investigated both experimentally and theoretically with few-cycle laser pulses. The main observables are the proton spectra associated with the H++H+ fragmentation channel. The model is based on the time-dependent Schrodinger equation and treats the electronic and nuclear coordinates on the same level. Therefore it allows the ultrafast nuclear dynamics to be followed as a function of the laser pulse duration, carrier-envelope phase offset, and peak intensity. We mainly report results in the sequential double-ionization regime above 2x10(14) W cm(-2). The proton spectra are shifted to higher energies as the pulse duration is reduced from 40 down to 10 fs. The good agreement between the model predictions and the experimental data at 10 fs permits a theoretical study with pulse durations down to a few femtoseconds. We demonstrate the very fast nuclear dynamics of the H-2 ion for a pulse duration as short as 1 fs between the two ionization events, giving H-2(+) from H-2 and H++H+ from H-2(+). The carrier-envelope phase offset plays a significant role only for pulse durations shorter than 4 fs. At 10 fs, the laser intensity dependence of the proton spectra is fairly well reproduced by the model. BibTeX: @article{SaugoutPRA2008, author = {Saugout, S. and Charron, E. and Cornaggia, C.}, title = {H-2 double ionization with few-cycle laser pulses}, journal = {Phys Rev A}, year = {2008}, volume = {77}, number = {2}, pages = {023404}, doi = {10.1103/PhysRevA.77.023404} }  "Two-color photoionization in XUV-FEL and laser fields"Taïeb R, Maquet A and Meyer M, Journal of Physics., In Journal of Physics: Conference Series. UK, 2008, 2008. Vol. 141, pp. 012017. IOP Publishing Ltd. - (2008). [Abstract] [BibTeX] Abstract: We address several questions related to the nonlinear ionization processes observed when atoms are in the simultaneous presence of intense and coherent infrared (IR) and extreme ultraviolet (XUV) laser pulses. This topic is of much interest in the context of the current development of new XUV coherent sources, either from high-order harmonics or from free-electron laser (FEL) devices, like the one available at FLASH in Hamburg, that can be synchronized with IR lasers. In this paper, we discuss the advantages and limitations of the so-called soft-photon approximation, which, we will show here, provides most useful insights in the analysis of different processes involving these two fields. BibTeX: @article{TaiebJP2008, author = {Taïeb, R. and Maquet, A. and Meyer, M.}, title = {Two-color photoionization in XUV-FEL and laser fields}, booktitle = {Journal of Physics: Conference Series}, journal = {Journal of Physics}, publisher = {IOP Publishing Ltd.}, year = {2008}, volume = {141}, pages = {012017}, note = {International Conference on Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces, 30 June-2 July 2008, Paris, France} }  "Quantum Path Interferences in High-Order Harmonic Generation"Zair A, Holler M, Guandalini A, Schapper F, Biegert J, Gallmann L, Keller U, Wyatt AS, Monmayrant A, Walmsley IA, Cormier E, Auguste T, Caumes JP and Salières P, Phys Rev Lett. Vol. 100(14), pp. 143902. APS - (2008). [BibTeX] [DOI] [URL] BibTeX: @article{ZairPRL2008, author = {A. Zair and M. Holler and A. Guandalini and F. Schapper and J. Biegert and L. Gallmann and U. Keller and A. S. Wyatt and A. Monmayrant and I. A. Walmsley and E. Cormier and T. Auguste and J. P. Caumes and P. Salières}, title = {Quantum Path Interferences in High-Order Harmonic Generation}, journal = {Phys Rev Lett}, publisher = {APS}, year = {2008}, volume = {100}, number = {14}, pages = {143902}, url = {http://link.aps.org/abstract/PRL/v100/e143902}, doi = {10.1103/PhysRevLett.100.143902} }  2007 "Numerical study of nanosecond laser interactions with micro-sized single droplets and sprays of xenon"Auguste T, de Gaufridy de Dortan F, Ceccotti T, Hergott JF, Sublemontier O, Descamps D and Schmidt M , Journal of Applied Physics. Vol. 101(4), pp. 043302. AIP - (2007). [BibTeX] [DOI] [URL] BibTeX: @article{AugusteJAP2007, author = {T. Auguste and F. de Gaufridy de Dortan and T. Ceccotti and J. F. Hergott and O. Sublemontier and D. Descamps and M. Schmidt}, title = {Numerical study of nanosecond laser interactions with micro-sized single droplets and sprays of xenon}, journal = {Journal of Applied Physics}, publisher = {AIP}, year = {2007}, volume = {101}, number = {4}, pages = {043302}, url = {http://link.aip.org/link/?JAP/101/043302/1}, doi = {10.1063/1.2432870} }  "Quasi-phase-matching of high-order harmonics using a modulated atomic density"Auguste T, Carré B and Salières P, Physical Review A (Atomic, Molecular, and Optical Physics). Vol. 76(1), pp. 011802. APS - (2007). [BibTeX] [DOI] [URL] BibTeX: @article{AugustePRA2007, author = {T. Auguste and B. Carré and P. Salières}, title = {Quasi-phase-matching of high-order harmonics using a modulated atomic density}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, publisher = {APS}, year = {2007}, volume = {76}, number = {1}, pages = {011802}, url = {http://link.aps.org/abstract/PRA/v76/e011802}, doi = {10.1103/PhysRevA.76.011802} }  "Characterization of attosecond pulse trains"Carré B, Mairesse Y, Agostini P, Breger P, Merdji H, Monchicourt P, Salières P, Varjů K, Johnsson P, Mauritsson J, L’Huillier A, Gustafsson E and Frasinski LJ, In Ultrafast Optics V, Springer Series in Optical Sciences. Vol. 132, pp. 45. Springer - (2007). [BibTeX] BibTeX: @incollection{CarreSSOS2007, author = {B. Carré and Y. Mairesse and P. Agostini and P. Breger and H. Merdji and P. Monchicourt and P. Salières and K. Varjů and P. Johnsson and J. Mauritsson and A. L’Huillier and E. Gustafsson and L. J. Frasinski}, editor = {S. Watanabe and K. Midorikawa}, title = {Characterization of attosecond pulse trains}, booktitle = {Ultrafast Optics V, Springer Series in Optical Sciences}, publisher = {Springer}, year = {2007}, volume = {132}, pages = {45} }  "First operation of SOLEIL, a third generation synchrotron radiation source in France and prospects for ARGEN-CIEL, a LINAC based fourth generation source"Couprie ME, Filhol JM, Benabderhammane C, Berteaud P, Besson JC, Briquez F, Brunelle P, Bruni C, Chubar O, Denard JC, Girault M, Godefroy JM, Herbaux C, Lebasque P, Le Roux V, Level MP, Lestrade A, Loulergue A, Marchand P, Marcouille O, Marteau F, Massala M, Nadji A, Nadolski L, Nagaoka R, Paulin F, Pottin B, Tordeux MA, Valleau M, Veteran J, Carré B, Garzella D, Labat M, Lambert G, Monot P, Jablonka M, Meot F, Mosnier A, Marques JR and Ortega JM, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment.,Vol. 575(1-2), pp. 7-10 - MAY 21, (2007). [BibTeX] [DOI] BibTeX: @article{CouprieNIM2007, author = {Couprie, M. E. and Filhol, J. M. and Benabderhammane, C. and Berteaud, P. and Besson, J. C. and Briquez, F. and Brunelle, P. and Bruni, C. and Chubar, O. and Denard, J. C. and Girault, M. and Godefroy, J. M. and Herbaux, C. and Lebasque, P. and Le Roux, V. and Level, M. P. and Lestrade, A. and Loulergue, A. and Marchand, P. and Marcouille, O. and Marteau, F. and Massala, M. and Nadji, A. and Nadolski, L. and Nagaoka, R. and Paulin, F. and Pottin, B. and Tordeux, M. A. and Valleau, M. and Veteran, J. and Carré, B. and Garzella, D. and Labat, M. and Lambert, G. and Monot, P. and Jablonka, M. and Meot, F. and Mosnier, A. and Marques, J. R. and Ortega, J. M.}, title = {First operation of SOLEIL, a third generation synchrotron radiation source in France and prospects for ARGEN-CIEL, a LINAC based fourth generation source}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2007}, volume = {575}, number = {1-2}, pages = {7-10}, doi = {10.1016/j.nima.2007.01.007} }  "High-order harmonic generation with a strong laser field and an attosecond-pulse train: The Dirac-Delta comb and monochromatic limits"de Morisson Faria CF and Salières P, Laser Physics., Vol. 17(4), pp. 390-400 - APR, (2007). [BibTeX] [DOI] BibTeX: @article{FariaLP2007, author = {de Morisson Faria, C. Figueira and Salières, P.}, title = {High-order harmonic generation with a strong laser field and an attosecond-pulse train: The Dirac-Delta comb and monochromatic limits}, journal = {Laser Physics}, year = {2007}, volume = {17}, number = {4}, pages = {390-400}, doi = {10.1134/S1054660X07040147} }  "Search for stable propagation of intense femtosecond laser pulses in gas"Giulietti A, Galimberti M, Gamucci A, Giulietti D, Gizzi LA, Koester P, Labate L, Tomassini P, Ceccotti T, D'Oliveira P, Auguste T, Monot P and Martin P, Laser And Particle Beams., Vol. 25(4), pp. 513-521 - DEC, (2007). [BibTeX] [DOI] BibTeX: @article{GiuliettiLPB2007, author = {Giulietti, A. and Galimberti, M. and Gamucci, A. and Giulietti, D. and Gizzi, L. A. and Koester, P. and Labate, L. and Tomassini, P. and Ceccotti, T. and D'Oliveira, P. and Auguste, T. and Monot, P. and Martin, P.}, title = {Search for stable propagation of intense femtosecond laser pulses in gas}, journal = {Laser And Particle Beams}, year = {2007}, volume = {25}, number = {4}, pages = {513-521}, doi = {10.1017/S0263034607000079} }  "Demonstration of a spatial filtering amplifier for high-order harmonics"Goddet JP, Sebban S, Morlens AS, Gautier J, Rousseau JP, Burgy F, Zeitoun P, Valentin C, Hauri C, Maynard G, Boudaa A, Caumes J-P, Merdji H, Mocek T, Kozlova M and Jakubczak K, Opt. Lett.. Vol. 32(11), pp. 1498-1500. OSA - (2007). [BibTeX] [URL] BibTeX: @article{GoddetOL2007, author = {J. Ph. Goddet and S. Sebban and A. S. Morlens and J. Gautier and J. Ph. Rousseau and F. Burgy and Ph. Zeitoun and C. Valentin and C. Hauri and G. Maynard and A. Boudaa and J.-P. Caumes and H. Merdji and T. Mocek and M. Kozlova and K. Jakubczak}, title = {Demonstration of a spatial filtering amplifier for high-order harmonics}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2007}, volume = {32}, number = {11}, pages = {1498--1500}, url = {http://ol.osa.org/abstract.cfm?URI=ol-32-11-1498} }  "Broadband attosecond pulse shaping"Gustafsson E, Ruchon T, Swoboda M, Remetter T, Pourtal E, Lopez-Martens R, Balcou P and L'Huillier A, Opt. Lett. Vol. 32(11), pp. 1353-1355. OSA - (2007). [BibTeX] [URL] BibTeX: @article{GustafssonOL2007, author = {E. Gustafsson and T. Ruchon and M. Swoboda and T. Remetter and E. Pourtal and R. Lopez-Martens and Ph. Balcou and A. L'Huillier}, title = {Broadband attosecond pulse shaping}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2007}, volume = {32}, number = {11}, pages = {1353--1355}, url = {http://ol.osa.org/abstract.cfm?URI=ol-32-11-1353} }  "Time resolved luminescence of solids excited by femtosecond VUV pulses and synchrotron radiation"Kirm M, Babin V, Feldbach E, Nagirnyi V, Vielhauer S, Guizard S, Carré B, Grazia MD, Merdji H, Belsky AN, Fedorov N and Martin P, Physica Status Solidi (c). Vol. 4(3), pp. 870-876 - (2007). [BibTeX] [URL] BibTeX: @article{KirmPSS2007, author = {Kirm, M. and Babin, V. and Feldbach, E. and Nagirnyi, V. and Vielhauer, S. and Guizard, S. and Carré, B. and Grazia, M. De and Merdji, H. and Belsky, A. N. and Fedorov, N. and Martin, P.}, title = {Time resolved luminescence of solids excited by femtosecond VUV pulses and synchrotron radiation}, journal = {Physica Status Solidi (c)}, year = {2007}, volume = {4}, number = {3}, pages = {870--876}, url = {http://dx.doi.org/10.1002/pssc.200673876} }  "Coherent harmonic generation on UVSOR-II storage ring"Labat M, Hosaka M, Mochihashi A, Shimada M, Katoh M, Lambert G, Hara T, Takashima Y and Couprie ME, European Physical Journal D., Vol. 44(1), pp. 187-200 - JUL, (2007). [BibTeX] [DOI] BibTeX: @article{LabatEPJD2007, author = {Labat, M. and Hosaka, M. and Mochihashi, A. and Shimada, M. and Katoh, M. and Lambert, G. and Hara, T. and Takashima, Y. and Couprie, M. -E.}, title = {Coherent harmonic generation on UVSOR-II storage ring}, journal = {European Physical Journal D}, year = {2007}, volume = {44}, number = {1}, pages = {187-200}, doi = {10.1140/epjd/e2007-00177-6} }  "Transient phase masks in high-harmonic generation"Mairesse Y, Dudovich N, Levesque J, Kartashov D, Villeneuve DM, Corkum PB and Auguste T, Opt. Lett. Vol. 32(4), pp. 436-438. OSA - (2007). [BibTeX] [URL] BibTeX: @article{MairesseOL2007, author = {Y. Mairesse and N. Dudovich and J. Levesque and D. Kartashov and D. M. Villeneuve and P. B. Corkum and T. Auguste}, title = {Transient phase masks in high-harmonic generation}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2007}, volume = {32}, number = {4}, pages = {436--438}, url = {http://ol.osa.org/abstract.cfm?URI=ol-32-4-436} }  "Isolated attosecond pulses using a detuned second-harmonic field"Merdji H, Auguste T, Boutu W, Caumes J-P, Carré B, Pfeifer T, Jullien A, Neumark DM and Leone SR, Opt. Lett. Vol. 32(21), pp. 3134-3136. OSA - (2007). [BibTeX] [URL] BibTeX: @article{MerdjiOL2007, author = {Hamed Merdji and Thierry Auguste and Willem Boutu and J.-Pascal Caumes and Bertrand Carré and Thomas Pfeifer and Aurélie Jullien and Daniel M. Neumark and Stephen R. Leone}, title = {Isolated attosecond pulses using a detuned second-harmonic field}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2007}, volume = {32}, number = {21}, pages = {3134--3136}, url = {http://ol.osa.org/abstract.cfm?URI=ol-32-21-3134} }  "Ultrafast Electronuclear Dynamics of H2 Double Ionization"Saugout S, Cornaggia C, Suzor-Weiner A and Charron E, Physical Review Letters. Vol. 98(25), pp. 253003. APS - (2007). [BibTeX] [DOI] [URL] BibTeX: @article{SaugoutPRL2007, author = {Sebastien Saugout and Christian Cornaggia and Annick Suzor-Weiner and Eric Charron}, title = {Ultrafast Electronuclear Dynamics of H2 Double Ionization}, journal = {Physical Review Letters}, publisher = {APS}, year = {2007}, volume = {98}, number = {25}, pages = {253003}, url = {http://link.aps.org/abstract/PRL/v98/e253003}, doi = {10.1103/PhysRevLett.98.253003} }  "Scaling of Wave-Packet Dynamics in an Intense Midinfrared Field"Tate J, Auguste T, Muller HG, Salières P, Agostini P and DiMauro LF, Physical Review Letters. Vol. 98(1), pp. 013901. APS - (2007). [BibTeX] [DOI] [URL] BibTeX: @article{TatePRL2007, author = {J. Tate and T. Auguste and H. G. Muller and P. Salières and P. Agostini and L. F. DiMauro}, title = {Scaling of Wave-Packet Dynamics in an Intense Midinfrared Field}, journal = {Physical Review Letters}, publisher = {APS}, year = {2007}, volume = {98}, number = {1}, pages = {013901}, url = {http://link.aps.org/abstract/PRL/v98/e013901}, doi = {10.1103/PhysRevLett.98.013901} }  "Status of the SPARC-X project"Vaccarezza C, Alesini D, Bellaveglia M, Bertolucci S, Boni R, Boscolo M, Castellano M, Clozza A, Cultrera L, Di Pirro G, Drago A, Esposito A, Ferrario M, Ficcadenti L, Filippetto D, Fusco V, Gallo A, Gatti G, Ghigo A, Ligi C, Marinelli A, Migliorati M, Mostacci A, Pace E, Palumbo L, Pellegrino L, Preger M, Ricci R, Sanelli C, Serio M, Sgamma F, Spataro B, Stella A, Tazzioli F, Vescovi M, Vicario C, Ciocci F, Dattoli G, Dipace A, Doria A, Flora F, Gallerano GP, Giannessi L, Giovenale E, Messina G, Ottaviani PL, Pagnutti S, Parisi G, Picardi L, Quattromini M, Renieri A, Ronci G, Ronsivalle C, Rosetti M, Sabia E, Sassi M, Torre A, Zucchini A, Mattioli M, Pelliccia D, Catani L, Chiadroni E, Cianchi A, Gabrielli E, Schaerf C, Musumeci P, Petrarca M, Alessandria F, Bacci A, Bonifacio R, Boscolo I, Broggi F, De Martinis C, Castelli F, Cialdi S, Giove D, Flacco A, Maroli C, Petrillo V, Rossi AR, Serafmi L, Perrone A, Labat M, Tcherbakoff O, Lambert G, Garzella D, Bougeard M, Breger P, Monchicourt P, Merdji H, Salieres P, Carre B, Couprie ME, Emma P, Pellegrini C, Reiche S and Rosenzweig J, In 2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11. , pp. 3200-3202 - (2007). [Abstract] [BibTeX] [DOI] Abstract: SPARC-X is a two branch project consisting in the SPARC test facility dedicated to the development and test of critical subsystems such as high brightness photoinjector and a modular expandable undulator for SASE-FEL experiments at 500 mn with seeding, and the SPARX facility aiming at generation of high brilliance coherent radiation in the 1.5-13 mn range, based on the achieved expertise. The projects are supported by MIUR (Research Department of Italian Government) and Regione Lazio. SPARC has completed the commissionmig phase of the photoinjector in November 2006. The achieved experimental results are here summarized together with the status of the second phase commissioning plans. The SPARX project is based on the generation of ultra high peak brightness electron beams at the energy of 1 and 2 GeV generating radiation in the 1.5-13 mn range. The construction is at the moment planned in two steps starting with a 1 GeV Linac. The project layout including both RF-compression and magnetic chicane techniques has been studied. BibTeX: @inproceedings{VaccarezzaTUPMN2007, author = {Vaccarezza, C. and Alesini, D. and Bellaveglia, M. and Bertolucci, S. and Boni, R. and Boscolo, M. and Castellano, M. and Clozza, A. and Cultrera, L. and Di Pirro, G. and Drago, A. and Esposito, A. and Ferrario, M. and Ficcadenti, L. and Filippetto, D. and Fusco, V. and Gallo, A. and Gatti, G. and Ghigo, A. and Ligi, C. and Marinelli, A. and Migliorati, M. and Mostacci, A. and Pace, E. and Palumbo, L. and Pellegrino, L. and Preger, M. and Ricci, R. and Sanelli, C. and Serio, M. and Sgamma, F. and Spataro, B. and Stella, A. and Tazzioli, F. and Vescovi, M. and Vicario, C. and Ciocci, F. and Dattoli, G. and Dipace, A. and Doria, A. and Flora, F. and Gallerano, G. P. and Giannessi, L. and Giovenale, E. and Messina, G. and Ottaviani, P. L. and Pagnutti, S. and Parisi, G. and Picardi, L. and Quattromini, M. and Renieri, A. and Ronci, G. and Ronsivalle, C. and Rosetti, M. and Sabia, E. and Sassi, M. and Torre, A. and Zucchini, A. and Mattioli, M. and Pelliccia, D. and Catani, L. and Chiadroni, E. and Cianchi, A. and Gabrielli, E. and Schaerf, C. and Musumeci, P. and Petrarca, M. and Alessandria, F. and Bacci, A. and Bonifacio, R. and Boscolo, I. and Broggi, F. and De Martinis, C. and Castelli, F. and Cialdi, S. and Giove, D. and Flacco, A. and Maroli, C. and Petrillo, V. and Rossi, A. R. and Serafmi, L. and Perrone, A. and Labat, M. and Tcherbakoff, O. and Lambert, G. and Garzella, D. and Bougeard, M. and Breger, P. and Monchicourt, P. and Merdji, H. and Salieres, P. and Carre, B. and Couprie, M. E. and Emma, P. and Pellegrini, C. and Reiche, S. and Rosenzweig, J.}, title = {Status of the SPARC-X project}, booktitle = {2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11}, year = {2007}, pages = {3200-3202}, note = {IEEE Particle Accelerator Conference, Albuquerque, NM, JUN 25-29, 2007}, doi = {10.1109/PAC.2007.4440962} }  "Subcycle dynamics in the laser ionization of molecules"Xie X, Wickenhauser M, Boutu W, Merdji H, Salières P and Scrinzi A, Physical Review A (Atomic, Molecular, and Optical Physics). Vol. 76(2), pp. 023426. APS - (2007). [BibTeX] [DOI] [URL] BibTeX: @article{XiePRA2007, author = {Xinhua Xie and M. Wickenhauser and W. Boutu and H. Merdji and P. Salières and A. Scrinzi}, title = {Subcycle dynamics in the laser ionization of molecules}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, publisher = {APS}, year = {2007}, volume = {76}, number = {2}, pages = {023426}, url = {http://link.aps.org/abstract/PRA/v76/e023426}, doi = {10.1103/PhysRevA.76.023426} }  "Two-quantum-path interferences in high order harmonic generation"Zair A, Holler M, Guandalini A, Schapper F, Biegert J, Keller U, Salieres P, Auguste T, Cormier E, Wyatt A, Monmayrant A and Walmsley I, In 2007 CONFERENCE ON LASERS and ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5. , pp. 2759-2760. - (2007). [Abstract] [BibTeX] Abstract: We have investigated intensity dependent high-harmonic generation, when short and long trajectories are both visible in the generated signal. We have measured a plateau-harmonic spectral broadening and yield modulations consistent with quantum-paths interferences calculations. (C) 2007 Optical Society of America BibTeX: @inproceedings{ZairCLEO2007, author = {Zair, A. and Holler, M. and Guandalini, A. and Schapper, F. and Biegert, J. and Keller, U. and Salieres, P. and Auguste, T. and Cormier, E. and Wyatt, A. and Monmayrant, A. and Walmsley, I.}, title = {Two-quantum-path interferences in high order harmonic generation}, booktitle = {2007 CONFERENCE ON LASERS and ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5}, year = {2007}, pages = {2759-2760}, note = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference, Baltimore, MD, MAY 06-11, 2007} }  2006 "Non-sequential double ionization of H2 using ultrashort 10 fs laser pulses"Beylerian C, Saugout S and Cornaggia C, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 39(6), pp. L105-L112 - (2006). [Abstract] [BibTeX] [URL] Abstract: Non-sequential double ionization of H2 is clearly observed using 10 fs laser pulses in the 1013-1014 W cm[?]2 intensity range using proton spectra from the H++H+ dissociation channel. Proton spectra recorded using linear and circular polarizations allow one to identify rescattering of the first ionized electron as the major effect responsible for non-sequential double ionization. At intensities below 1014 W cm[?]2, double ionization is dominated by recollision excitation of H+2 followed by field ionization of transient excited states. Comparisons with spectra recorded at 40 fs show that sequential double ionization paths and the related charge resonance enhanced ionization are severely reduced at 10 fs and low laser intensities because H+2 does not have enough time to stretch up to internuclear distances where ionization rates are very high. BibTeX: @article{BeylerianJPB2006, author = {C Beylerian and S Saugout and C Cornaggia}, title = {Non-sequential double ionization of H2 using ultrashort 10 fs laser pulses}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2006}, volume = {39}, number = {6}, pages = {L105-L112}, url = {http://stacks.iop.org/0953-4075/39/L105} }  "Femtosecond spectroscopic study of carminic acid-DNA interactions"Comanici R, Gabel B, Gustavsson T, Markovitsi D, Cornaggia C, Pommeret S, Rusu C and Kryschi C , Chemical Physics., Vol. 325(2), pp. 509-518 - JUN 20, (2006). [BibTeX] [DOI] BibTeX: @article{ComaniciCP2006, author = {Comanici, R and Gabel, B and Gustavsson, T and Markovitsi, D and Cornaggia, C and Pommeret, S and Rusu, C and Kryschi, C}, title = {Femtosecond spectroscopic study of carminic acid-DNA interactions}, journal = {Chemical Physics}, year = {2006}, volume = {325}, number = {2}, pages = {509-518}, doi = {10.1016/j.chemphys.2006.01.026} }  "Second generation X-ray lasers"Fajardo M, Zeitoun P, Faivre G, Sebban S, Mocek T, Hallou A, Aubert D, Balcou P, Burgy F, Douillet D, Mercere P, Morlens A, Rousseau J, Valentin C, Kazamias S, de Lacheze-Murel G, Lefrou T, Merdji H, le Pape S, Ravet M, Delmotte F and Gautier J, Journal Of Quantitative Spectroscopy and Radiative Transfer., Vol. 99(1-3), pp. 142-152 -MAY-JUN, (2006). [BibTeX] [DOI] BibTeX: @article{FajardoJQSRT2006, author = {Fajardo, M and Zeitoun, P and Faivre, G and Sebban, S and Mocek, T and Hallou, A and Aubert, D and Balcou, P and Burgy, F and Douillet, D and Mercere, P and Morlens, AS and Rousseau, JP and Valentin, C and Kazamias, S and de Lacheze-Murel, G and Lefrou, T and Merdji, H and le Pape, S and Ravet, MF and Delmotte, F and Gautier, J}, title = {Second generation X-ray lasers}, journal = {Journal Of Quantitative Spectroscopy and Radiative Transfer}, year = {2006}, volume = {99}, number = {1-3}, pages = {142-152}, doi = {10.1016/j.jqsrt.2005.05.011} }  "Controlling high-order harmonic generation and above-threshold ionization with an attosecond-pulse train"de Morisson Faria CF, Salières P, Villain P and Lewenstein M, Physical Review A (Atomic, Molecular, and Optical Physics). Vol. 74(5), pp. 053416. APS - (2006). [BibTeX] [DOI] [URL] BibTeX: @article{FariaPRA2006, author = {C. Figueira de Morisson Faria and P. Salières and P. Villain and M. Lewenstein}, title = {Controlling high-order harmonic generation and above-threshold ionization with an attosecond-pulse train}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, publisher = {APS}, year = {2006}, volume = {74}, number = {5}, pages = {053416}, url = {http://link.aps.org/abstract/PRA/v74/e053416}, doi = {10.1103/PhysRevA.74.053416} }  "Prepulse effect on intense femtosecond laser pulse propagation in gas"Giulietti A, Tomassini P, Galimberti M, Giulietti D, Gizzi LA, Koester P, Labate L, Ceccotti T, D'Oliveira P, Auguste T, Monot P and Martin P, Physics of Plasmas. Vol. 13(9), pp. 093103. AIP - (2006). [BibTeX] [DOI] [URL] BibTeX: @article{GiuliettiPP2006, author = {Antonio Giulietti and Paolo Tomassini and Marco Galimberti and Danilo Giulietti and Leonida A. Gizzi and Petra Koester and Luca Labate and Tiberio Ceccotti and Pascal D'Oliveira and Thierry Auguste and Pascal Monot and Philippe Martin}, title = {Prepulse effect on intense femtosecond laser pulse propagation in gas}, journal = {Physics of Plasmas}, publisher = {AIP}, year = {2006}, volume = {13}, number = {9}, pages = {093103}, url = {http://link.aip.org/link/?PHP/13/093103/1}, doi = {10.1063/1.2351961} }  "Spectroscopy of transient conductivity in diamond induced by ultra-short laser pulses in the spectral range from IR to VUV"Klimentov SM, Gaudin J, Guizard S, Pivovarov PA, Garnov SV, Esnouf S, Petite G, Carré B and Martin P, ICONO 2005: Nonlinear Laser Spectroscopy, High Precision Measurements, and Laser Biomedicine and Chemistry. Vol. 6257(1), pp. 625705. SPIE - (2006). [BibTeX] [DOI] [URL] BibTeX: @article{KlimentovSPIE2006, author = {S. M. Klimentov and J. Gaudin and S. Guizard and P. A. Pivovarov and S. V. Garnov and S. Esnouf and G. Petite and B. Carré and P. Martin}, editor = {Sergey N. Bagayev and Andrey Chikishev and Alexander Dmitriev and Martial Ducloy and Tony Heinz and Vladilen Letokhov and Alexander Shkurinov and Hiroaki Takahashi}, title = {Spectroscopy of transient conductivity in diamond induced by ultra-short laser pulses in the spectral range from IR to VUV}, journal = {ICONO 2005: Nonlinear Laser Spectroscopy, High Precision Measurements, and Laser Biomedicine and Chemistry}, publisher = {SPIE}, year = {2006}, volume = {6257}, number = {1}, pages = {625705}, url = {http://link.aip.org/link/?PSI/6257/625705/1}, doi = {10.1117/12.677921} }  "Longitudinal and transverse heating of a relativistic electron bunch induced by a storage ring free electron laser"Labat M, Couprie M-E, Hosaka M, Mochihashi A, Katoh M and Takashima Y, Phys. Rev. ST Accel. Beams., Vol. 9(10), pp. 100701. American Physical Society - Oct, (2006). [BibTeX] [DOI] BibTeX: @article{LabatPRSTAB2006, author = {Labat, M. and Couprie, M.-E. and Hosaka, M. and Mochihashi, A. and Katoh, M. and Takashima, Y.}, title = {Longitudinal and transverse heating of a relativistic electron bunch induced by a storage ring free electron laser}, journal = {Phys. Rev. ST Accel. Beams}, publisher = {American Physical Society}, year = {2006}, volume = {9}, number = {10}, pages = {100701}, doi = {10.1103/PhysRevSTAB.9.100701} }  "Macroscopic control of high-order harmonics quantum-path components for the generation of attosecond pulses"Merdji H, Kovacev M, Boutu W, Salières P, Vernay F and Carré B, Physical Review A (Atomic, Molecular, and Optical Physics). Vol. 74(4), pp. 043804. APS - (2006). [BibTeX] [DOI] [URL] BibTeX: @article{MerdjiPRA2006, author = {H. Merdji and M. Kovacev and W. Boutu and P. Salières and F. Vernay and B. Carré}, title = {Macroscopic control of high-order harmonics quantum-path components for the generation of attosecond pulses}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, publisher = {APS}, year = {2006}, volume = {74}, number = {4}, pages = {043804}, url = {http://link.aps.org/abstract/PRA/v74/e043804}, doi = {10.1103/PhysRevA.74.043804} }  "Submicrometer digital in-line holographic microscopy at 32 nm with high-order harmonics"Morlens A-S, Gautier J, Rey G, Zeitoun P, Caumes J-P, Kos-Rosset M, Merdji H, Kazamias S, Cassou K and Fajardo M, Opt. Lett. Vol. 31(21), pp. 3095-3097. OSA - (2006). [BibTeX] [URL] BibTeX: @article{MorlensOL2006, author = {Anne-Sophie Morlens and Julien Gautier and Gilles Rey and Philippe Zeitoun and Jean-Pascal Caumes and Marylène Kos-Rosset and Hamed Merdji and Sophie Kazamias and Kevin Cassou and Marta Fajardo}, title = {Submicrometer digital in-line holographic microscopy at 32 nm with high-order harmonics}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2006}, volume = {31}, number = {21}, pages = {3095--3097}, url = {http://ol.osa.org/abstract.cfm?URI=ol-31-21-3095} }  "Free-electron laser dynamics in storage ring with a low emittance and momentum compaction factor configuration"Orlandi GL, Bruni C, Garzella D, Couprie M-E, De Ninno G, Bartolini R, Giannessi L and Dattoli G, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 568(2), pp. 520-531 -DEC 1, (2006). [BibTeX] [DOI] BibTeX: @article{OrlandiNIM2006, author = {Orlandi, G. L. and Bruni, C. and Garzella, D. and Couprie, M.-E. and De Ninno, G. and Bartolini, R. and Giannessi, L. and Dattoli, G.}, title = {Free-electron laser dynamics in storage ring with a low emittance and momentum compaction factor configuration}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2006}, volume = {568}, number = {2}, pages = {520-531}, doi = {10.1016/j.nima.2006.07.046} }  "A dipole interaction model for magnetochiral birefringence"Ruchon T, Vallet M, Chauvat D and Le Floch A, The Journal of Chemical Physics., Vol. 125, pp. 4104 - August, (2006). [Abstract] [BibTeX] [DOI] Abstract: We have developed a classical model to investigate the magnetochiral birefringence of an isotropic chiral medium submitted to a longitudinal magnetic field. This model, which is an extension of the atom dipole interaction model, yields direct calculations from the polarizabilities and positions of the atoms of the considered molecules. The numerical values obtained for the magnetochiral birefringence, as well as for the optical activity and Faraday rotation, are supported by the previously published experimental results on limonene, proline, and tartaric acid. BibTeX: @article{RuchonJCP2006, author = {Ruchon, T. and Vallet, M. and Chauvat, D. and Le Floch, A.}, title = {A dipole interaction model for magnetochiral birefringence}, journal = {The Journal of Chemical Physics}, year = {2006}, volume = {125}, pages = {4104}, doi = {10.1063/1.2211613} }  "Temporal separation of H2 double-ionization channels using intense ultrashort 10-fs laser pulses"Saugout S and Cornaggia C, Physical Review A (Atomic, Molecular, and Optical Physics). Vol. 73(4), pp. 041406. APS - (2006). [BibTeX] [DOI] [URL] BibTeX: @article{SaugoutPRA2006, author = {S. Saugout and C. Cornaggia}, title = {Temporal separation of H2 double-ionization channels using intense ultrashort 10-fs laser pulses}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, publisher = {APS}, year = {2006}, volume = {73}, number = {4}, pages = {041406}, url = {http://link.aps.org/abstract/PRA/v73/e041406}, doi = {10.1103/PhysRevA.73.041406} }  "Angularly resolved electron wave packet interferences "Varjú K, Johnsson P, Mauritsson J, Remetter T, Ruchon T, Ni Y, Lépine F, Kling M, Khan J, Schafer KJ, Vrakking MJJ and L'Huillier A, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 39(18), pp. 3983-3991 - (2006). [Abstract] [BibTeX] [URL] Abstract: We study experimentally the ionization of argon atoms by a train of attosecond pulses in the presence of a strong infrared laser field, using a velocity map imaging technique. The recorded momentum distribution strongly depends on the delay between the attosecond pulses and the laser field. We interpret the interference patterns observed for different delays using numerical and analytical calculations within the strong field approximation. BibTeX: @article{VarjuJPB2006, author = {K Varjú and P Johnsson and J Mauritsson and T Remetter and T Ruchon and Y Ni and F Lépine and M Kling and J Khan and K J Schafer and M J J Vrakking and A L'Huillier}, title = {Angularly resolved electron wave packet interferences }, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2006}, volume = {39}, number = {18}, pages = {3983-3991}, url = {http://stacks.iop.org/0953-4075/39/3983} }  "Generation of attosecond pulses in molecular nitrogen"Wabnitz H, Mairesse Y, Frasinski LJ, Stankiewicz M, Boutu W, Breger P, Johnsson P, Merdji H, Monchicourt P, Salières P, Varjů K, Vitteau M and Carré B, European Physical Journal D., Vol. 40(2), pp. 305-311 - NOV, (2006). [BibTeX] [DOI] BibTeX: @article{WabnitzEPJD2006, author = {Wabnitz, H. and Mairesse, Y. and Frasinski, L. J. and Stankiewicz, M. and Boutu, W. and Breger, P. and Johnsson, P. and Merdji, H. and Monchicourt, P. and Salières, P. and Varjů, K. and Vitteau, M. and Carré, B.}, title = {Generation of attosecond pulses in molecular nitrogen}, journal = {European Physical Journal D}, year = {2006}, volume = {40}, number = {2}, pages = {305-311}, doi = {10.1140/epjd/e2006-00148-5} }  "Suppression of limit cycles in a free electron laser",Bruni C, Bielawski S, Orlandi GL, Garzella D and Couprie M-E, European Physical Journal D. Vol. 39(1), pp. 75-85 - (2005). [BibTeX] BibTeX: @article{BruniEPJD2006, author = {Bruni, C. and Bielawski, S. and Orlandi, G. L. and Garzella, D. and Couprie, M.-E.}, title = {Suppression of limit cycles in a free electron laser}, journal = {European Physical Journal D}, year = {2005}, volume = {39}, number = {1}, pages = {75-85} }  2005 "Advection-Induced Spectrotemporal Defects in a Free-Electron Laser"Bielawski S, Szwaj C, Bruni C, Garzella D, Orlandi GL and Couprie M-E, Physical Review Letters. Vol. 95(3), pp. 034801. APS. - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{BielawskiPRL2005, author = {S. Bielawski and C. Szwaj and C. Bruni and D. Garzella and G. L. Orlandi and M.-E. Couprie}, title = {Advection-Induced Spectrotemporal Defects in a Free-Electron Laser}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {95}, number = {3}, pages = {034801}, url = {http://link.aps.org/abstract/PRL/v95/e034801}, doi = {10.1103/PhysRevLett.95.034801} }  "Pulse compression with time-domain optimized chirped mirrors"Dombi P, Yakovlev VS, O'Keeffe K, Fuji T, Lezius M and Tempea G, Opt. Express. Vol. 13(26), pp. 10888-10894. OSA - (2005). [BibTeX] [URL] BibTeX: @article{DombiOE2005, author = {P. Dombi and V. S. Yakovlev and K. O'Keeffe and T. Fuji and M. Lezius and G. Tempea}, title = {Pulse compression with time-domain optimized chirped mirrors}, journal = {Opt. Express}, publisher = {OSA}, year = {2005}, volume = {13}, number = {26}, pages = {10888--10894}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-13-26-10888} }  "Attosecond Electron Wave Packet Dynamics in Strong Laser Fields"Johnsson P, Lopez-Martens R, Kazamias S, Mauritsson J, Valentin C, Remetter T, Varjů K, Gaarde MB, Mairesse Y, Wabnitz H, Salières P, Balcou P, Schafer KJ and L'Huillier A, Physical Review Letters. Vol. 95(1), pp. 013001. APS - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{JohnssonPRL2005, author = {P. Johnsson and R. Lopez-Martens and S. Kazamias and J. Mauritsson and C. Valentin and T. Remetter and K. Varjů and M. B. Gaarde and Y. Mairesse and H. Wabnitz and P. Salières and Ph. Balcou and K. J. Schafer and A. L'Huillier}, title = {Attosecond Electron Wave Packet Dynamics in Strong Laser Fields}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {95}, number = {1}, pages = {013001}, url = {http://link.aps.org/abstract/PRL/v95/e013001}, doi = {10.1103/PhysRevLett.95.013001} }  "Extreme Ultraviolet Fourier-Transform Spectroscopy with High Order Harmonics"Kovacev M, Fomichev SV, Priori E, Mairesse Y, Merdji H, Monchicourt P, Breger P, Norin J, Persson A, L'Huillier A, Wahlstrom C-G, Carré B and Salières P, Physical Review Letters. Vol. 95(22), pp. 223903. APS - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{KovacevPRL2005, author = {M. Kovacev and S. V. Fomichev and E. Priori and Y. Mairesse and H. Merdji and P. Monchicourt and P. Breger and J. Norin and A. Persson and A. L'Huillier and C.-G. Wahlstrom and B. Carré and P. Salières}, title = {Extreme Ultraviolet Fourier-Transform Spectroscopy with High Order Harmonics}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {95}, number = {22}, pages = {223903}, url = {http://link.aps.org/abstract/PRL/v95/e223903}, doi = {10.1103/PhysRevLett.95.223903} }  "Amplitude and Phase Control of Attosecond Light Pulses"Lopez-Martens R, Varjů K, Johnsson P, Mauritsson J, Mairesse Y, Salières P, Gaarde MB, Schafer KJ, Persson A, Svanberg S, Wahlstrom C-G and L'Huillier A, Physical Review Letters. Vol. 94(3), pp. 033001. APS - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{LopezmartensPRL2005, author = {Rodrigo Lopez-Martens and Katalin Varjů and Per Johnsson and Johan Mauritsson and Yann Mairesse and Pascal Salières and Mette B. Gaarde and Kenneth J. Schafer and Anders Persson and Sune Svanberg and Claes-Goran Wahlstrom and Anne L'Huillier}, title = {Amplitude and Phase Control of Attosecond Light Pulses}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {94}, number = {3}, pages = {033001}, url = {http://link.aps.org/abstract/PRL/v94/e033001}, doi = {10.1103/PhysRevLett.94.033001} }  "High-harmonics chirp and optimization of attosecond pulse trains" Mairesse Y, de Bohan A, Frasinski L, Merdji H, Dinu L, Monchicourt P, Breger P, Kovacev M, Auguste T, Carré B, Muller H, Agostini P and Salières P, Laser Physics., Vol. 15(6), pp. 863-870 - JUN, (2005). [BibTeX] BibTeX: @article{MairesseLP2005, author = {Mairesse, Y and de Bohan, A and Frasinski, LJ and Merdji, H and Dinu, LC and Monchicourt, P and Breger, P and Kovacev, M and Auguste, T and Carré, B and Muller, HG and Agostini, P and Salières, P}, title = {High-harmonics chirp and optimization of attosecond pulse trains}, journal = {Laser Physics}, year = {2005}, volume = {15}, number = {6}, pages = {863-870} }  "High Harmonic XUV Spectral Phase Interferometry for Direct Electric-Field Reconstruction"Mairesse Y, Gobert O, Breger P, Merdji H, Meynadier P, Monchicourt P, Perdrix M, Salières P and Carré B, Physical Review Letters. Vol. 94(17), pp. 173903. APS - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{MairessePRL2005, author = {Y. Mairesse and O. Gobert and P. Breger and H. Merdji and P. Meynadier and P. Monchicourt and M. Perdrix and P. Salières and B. Carré}, title = {High Harmonic XUV Spectral Phase Interferometry for Direct Electric-Field Reconstruction}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {94}, number = {17}, pages = {173903}, url = {http://link.aps.org/abstract/PRL/v94/e173903}, doi = {10.1103/PhysRevLett.94.173903} }  "ASE contrast improvement with a non-linear filtering Sagnac interferometer"Renault A, Augé-Rochereau F, Planchon T, D'Oliveira P, Auguste T, Chériaux G and Chambaret J-P , Optics Communications., Vol. 248(4-6), pp. 535-541 - April, (2005). [Abstract] [BibTeX] [URL] Abstract: A new method to improve the temporal contrast of an ultra-short laser pulse has been developed. This technique uses a Sagnac interferometer in combination with a non-linear medium. A phase shift induced in the ultra-short pulse by non-linear effect separates it from the amplified spontaneous emission background. Experiments with a 1 kHz, 55 fs, 1 mJ Ti:Sa laser were performed. The temporal contrast measurements have shown a contrast improvement of four orders of magnitude. BibTeX: @article{RenaultOC2005, author = {Renault, Amandine and Augé-Rochereau, Frédérika and Planchon, Thomas and D'Oliveira, Pascal and Auguste, Thierry and Chériaux, Gilles and Chambaret, Jean-Paul}, title = {ASE contrast improvement with a non-linear filtering Sagnac interferometer}, journal = {Optics Communications}, year = {2005}, volume = {248}, number = {4-6}, pages = {535--541}, url = {http://www.sciencedirect.com/science/article/B6TVF-4F3FBHF-2/1/ffd6c1cdb79f3b1e6b097d4fd15f9123} }  "The magneto-optical properties of diastereoisomers"Ruchon T, Thépot J-Y, Vallet M and Floch AL, Chemical Physics Letters. Vol. 412(4-6), pp. 411 - 415 - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{RuchonCPL2005, author = {Thierry Ruchon and Jean-Yves Thépot and Marc Vallet and Albert Le Floch}, title = {The magneto-optical properties of diastereoisomers}, journal = {Chemical Physics Letters}, year = {2005}, volume = {412}, number = {4-6}, pages = {411 - 415}, url = {http://www.sciencedirect.com/science/article/pii/S0009261405009966}, doi = {10.1016/j.cplett.2005.07.034} }  "Experimental investigation of the magnetochiral index in liquids"Ruchon T, Vallet M, Chauvat D, Le Floch A and Thépot J-Y, Phys. Rev. A., Vol. 72, pp. 043405. American Physical Society - Oct, (2005). [Abstract] [BibTeX] [DOI] [URL] Abstract: We showed through experiments that the magnetochiral index is polarization invariant and reported its wavelength dependence. These properties were investigated with limonene and using a specially-designed Ar+ -ring active interferometer. A Fresnel drag-type optical bias inside the discharge tube, combined with two calibrations and the circumvention of systematic errors, allowed us to reach a detection level in the range of 10-12 when measuring the change in the magnetochiral index of intracavity liquid samples. Our results are in agreement with the different predictions made for magnetochiral refraction. BibTeX: @article{RuchonPRA2005, author = {Ruchon, Thierry and Vallet, Marc and Chauvat, Dominique and Le Floch, Albert and Thépot, Jean-Yves}, title = {Experimental investigation of the magnetochiral index in liquids}, journal = {Phys. Rev. A}, publisher = {American Physical Society}, year = {2005}, volume = {72}, pages = {043405}, url = {http://link.aps.org/doi/10.1103/PhysRevA.72.043405}, doi = {10.1103/PhysRevA.72.043405} }  "Frequency chirp of harmonic and attosecond pulses"Varjů K, Mairesse Y, Carré B, Gaarde M, Johnsson P, Kazamias S, Lopez-Martens R, Mauritsson J, Schafer K, Balcou P, L'Huillier A and Salières P, Journal of Modern Optics., Vol. 52(2-3), pp. 379-394 - JAN-FEB, (2005). [BibTeX] [DOI] BibTeX: @article{VarjuJMO2005, author = {Varjů, K and Mairesse, Y and Carré, B and Gaarde, MB and Johnsson, P and Kazamias, S and Lopez-Martens, R and Mauritsson, J and Schafer, KJ and Balcou, PH and L'Huillier, A and Salières, P}, title = {Frequency chirp of harmonic and attosecond pulses}, journal = {Journal of Modern Optics}, year = {2005}, volume = {52}, number = {2-3}, pages = {379-394}, doi = {10.1080/09500340412331301542} }  "Reconstruction of Attosecond Pulse Trains Using an Adiabatic Phase Expansion",Varjů K, Mairesse Y, Agostini P, Breger P, Carré B, Frasinski LJ, Gustafsson E, Johnsson P, Mauritsson J, Merdji H, Monchicourt P, L'Huillier A and Salières P, Physical Review Letters. Vol. 95(24), pp. 243901. APS - (2005). [BibTeX] [DOI] [URL] BibTeX: @article{VarjuPRL2005, author = {K. Varjů and Y. Mairesse and P. Agostini and P. Breger and B. Carré and L. J. Frasinski and E. Gustafsson and P. Johnsson and J. Mauritsson and H. Merdji and P. Monchicourt and A. L'Huillier and P. Salières}, title = {Reconstruction of Attosecond Pulse Trains Using an Adiabatic Phase Expansion}, journal = {Physical Review Letters}, publisher = {APS}, year = {2005}, volume = {95}, number = {24}, pages = {243901}, url = {http://link.aps.org/abstract/PRL/v95/e243901}, doi = {10.1103/PhysRevLett.95.243901} }  2004 "Storage ring free electron laser dynamics in presence of an auxiliary harmonic radio frequency cavity"Thomas CA, Botman JIM, Bruni C, Orlandi GL, de Ninno G, Garzella D and Couprie M-E, European Physical Journal D., Vol. 32(1), pp. 83-93 - JAN, (2005). [BibTeX] [DOI] BibTeX: @article{ThomasEPJD2004, author = {Thomas, C A and Botman, J I M and Bruni, C and Orlandi, G L and de Ninno, G and Garzella, D and Couprie, M-E}, title = {Storage ring free electron laser dynamics in presence of an auxiliary harmonic radio frequency cavity}, journal = {European Physical Journal D}, year = {2005}, volume = {32}, number = {1}, pages = {83-93}, doi = {10.1140/epjd/e2004-00200-6} }  "Saturation and electron-beam lifetime in a storage ring free-electron laser"Bartolini R, Dattoli G, Giannessi L, Mezi L, Renieri A, Migliorati M, Bruni C, Couprie ME, Garzella D and Orlandi G, Physical Review E (Statistical, Nonlinear, and Soft Matter Physics). Vol. 69(3), pp. 036501. APS - (2004). [BibTeX] [DOI] [URL] BibTeX: @article{BartoliniPRE2004, author = {R. Bartolini and G. Dattoli and L. Giannessi and L. Mezi and A. Renieri and M. Migliorati and C. Bruni and M. E. Couprie and D. Garzella and G. Orlandi}, title = {Saturation and electron-beam lifetime in a storage ring free-electron laser}, journal = {Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)}, publisher = {APS}, year = {2004}, volume = {69}, number = {3}, pages = {036501}, url = {http://link.aps.org/abstract/PRE/v69/e036501}, doi = {10.1103/PhysRevE.69.036501} }  "Coulomb explosion imaging of fragmentation channels following laser-induced double ionization of N2"Beylerian C and Cornaggia C, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 37(13), pp. L259-L265 - (2004). [Abstract] [BibTeX] [URL] Abstract: Laser-induced double ionization of the N2 molecule leads to non-Coulombic N+ + N+ and N2+ + N fragmentation channels, with well-defined kinetic energy release spectra. The associated fragmentation temporal dynamics is probed using a femtosecond pump-probe scheme based on Coulomb explosion of the dissociating system. The probe laser pulse produces the double ionization of the dissociating N2+2 ion, and the detected probe signal is the energy spectrum of the resulting N2+ + N2+ dissociation channel. The probe excitation takes place at internuclear distances larger than 5 Å, where the N2+ + N2+ dissociation imaging channel energy is Coulombic. This excitation scheme allows us to reproduce the N2+2 fragmentation temporal dynamics using a simple model which takes into account the long-range potentials of the N+ + N+ and N2+ + N pathways and the short-range dissociation times. BibTeX: @article{BeylerianJPB2004, author = {C Beylerian and C Cornaggia}, title = {Coulomb explosion imaging of fragmentation channels following laser-induced double ionization of N2}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2004}, volume = {37}, number = {13}, pages = {L259-L265}, url = {http://stacks.iop.org/0953-4075/37/L259} }  "Suppression of the pulsed regimes appearing in free-electron lasers using feedback control of an unstable stationary state"Bielawski S, Bruni C, Orlandi GL, Garzella D and Couprie ME (2004), , Phys. Rev. E., Vol. 69(4), pp. 045502. American Physical Society - Apr, (2004). [BibTeX] [DOI] BibTeX: @article{BielawskiPRE2004, author = {Bielawski, S. and Bruni, C. and Orlandi, G. L. and Garzella, D. and Couprie, M. E.}, title = {Suppression of the pulsed regimes appearing in free-electron lasers using feedback control of an unstable stationary state}, journal = {Phys. Rev. E}, publisher = {American Physical Society}, year = {2004}, volume = {69}, number = {4}, pages = {045502}, doi = {10.1103/PhysRevE.69.045502} }  "Observation of Laser Driven Supercritical Radiative Shock Precursors"Bouquet S, Stéhlé C, Koenig M, Chièze J-P, Benuzzi-Mounaix A, Batani D, Leygnac S, Fleury X, Merdji H, Michaut C, Thais F, Grandjouan N, Hall T, Henry E, Malka V and Lafon J-PJ (2004), , Phys. Rev. Lett.., Vol. 92(22), pp. 225001. American Physical Society - Jun, (2004). [BibTeX] [DOI] BibTeX: @article{BouquetPRL2004, author = {Bouquet, S. and Stéhlé, C. and Koenig, M. and Chièze, J.-P. and Benuzzi-Mounaix, A. and Batani, D. and Leygnac, S. and Fleury, X. and Merdji, H. and Michaut, C. and Thais, F. and Grandjouan, N. and Hall, T. and Henry, E. and Malka, V. and Lafon, J.-P. J.}, title = {Observation of Laser Driven Supercritical Radiative Shock Precursors}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {2004}, volume = {92}, number = {22}, pages = {225001}, doi = {10.1103/PhysRevLett.92.225001} }  "Chaotic nature of the super-ACO FEL"Bruni C, Garzella D, Orlandi GL and Couprie M-E, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 528(1-2), pp. 273-277 - AUG 1, (2004). [BibTeX] [DOI] BibTeX: @article{BruniNIM2004, author = {Bruni, C and Garzella, D and Orlandi, G L and Couprie, M.-E.}, title = {Chaotic nature of the super-ACO FEL}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2004}, volume = {528}, number = {1-2}, pages = {273-277}, doi = {10.1016/j.nima.2004.04.069} }  "Stabilization of the naturally pulsed zones of the Super-ACO Storage Ring Free Electron Laser"Couprie M-E, Bruni C, Orlandi GL, Garzella D and Bielawski S , Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 528(1-2), pp. 263-267 - AUG 1, (2004). [BibTeX] [DOI] BibTeX: @article{CouprieNIM2004, author = {Couprie, M-E and Bruni, C and Orlandi, G L and Garzella, D and Bielawski, S}, title = {Stabilization of the naturally pulsed zones of the Super-ACO Storage Ring Free Electron Laser}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2004}, volume = {528}, number = {1-2}, pages = {263-267}, doi = {10.1016/j.nima.2004.04.060} }  "A French proposal for an innovative accelerators based coherent UV-X-ray source"Couprie M-E, Belakhovsky M, Gliquin B, Garzella D, Jablonka M, Meot F, Monot P, Mosnier A, Nahon L and Rousse A, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 528(1-2), pp. 557-561 - AUG 1, (2004). [BibTeX] [DOI] BibTeX: @article{CouprieNIM2004b, author = {Couprie, M-E and Belakhovsky, M and Gliquin, B and Garzella, D and Jablonka, M and Meot, F and Monot, P and Mosnier, A and Nahon, L and Rousse, A}, title = {A French proposal for an innovative accelerators based coherent UV-X-ray source}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2004}, volume = {528}, number = {1-2}, pages = {557-561}, doi = {10.1016/j.nima.2004.04.101} }  "Control of the electron beam vertical instability using the super-ACO free electron laser"Couprie M-E, Bruni C, Orlandi GL, Garzella D and Dattoli G, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 528(1-2), pp. 287-290 - AUG 1, (2004). [BibTeX] [DOI] BibTeX: @article{CouprieNIM2004c, author = {Couprie, M-E and Bruni, C and Orlandi, G L and Garzella, D and Dattoli, G}, title = {Control of the electron beam vertical instability using the super-ACO free electron laser}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2004}, volume = {528}, number = {1-2}, pages = {287-290}, doi = {10.1016/j.nima.2004.04.072} }  "First results on tunneling ionization of H2 with a new portable experiment"Fabre B, Posthumus J, Malfaire L, Staicu-Casagrande E, Jureta J, Cornaggia C, Baldit E and Urbain X, Laser Physics., Vol. 14(4), pp. 468-472 - APR, (2004). [BibTeX] BibTeX: @article{FabreLP2004, author = {Fabre, B and Posthumus, JH and Malfaire, L and Staicu-Casagrande, EM and Jureta, J and Cornaggia, C and Baldit, E and Urbain, X}, title = {First results on tunneling ionization of H2 with a new portable experiment}, journal = {Laser Physics}, year = {2004}, volume = {14}, number = {4}, pages = {468-472} }  "Using VUV high-order harmonics generated in gas as a seed for single pass FEL"Garzella D, Hara T, Carré B, Salières P, Shintake T, Kitamura H and Couprie M-E, Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment., Vol. 528(1-2), pp. 502-505 - AUG 1, (2004). [BibTeX] [DOI] BibTeX: @article{GarzellaNIM2004, author = {Garzella, D and Hara, T and Carré, B and Salières, P and Shintake, T and Kitamura, H and Couprie, M-E}, title = {Using VUV high-order harmonics generated in gas as a seed for single pass FEL}, journal = {Nuclear Instruments and Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment}, year = {2004}, volume = {528}, number = {1-2}, pages = {502-505}, doi = {10.1016/nima.2004.04.089} }  "Photoconductivity and photoemission studies of diamond irradiated by ultrashort VUV pulses"Gaudin J, Geoffroy G, Guizard S, Petite G, Klimentov S, Garnov S, Pivovarov P, Carré B, Belsky A and Martin P, Applied Physics B-Lasers and Optics., Vol. 78(7-8), pp. 1001-1004 - MAY, (2004). [BibTeX] [DOI] BibTeX: @article{GaudinAPB2004, author = {Gaudin, J and Geoffroy, G and Guizard, S and Petite, G and Klimentov, SM and Garnov, SV and Pivovarov, PA and Carré, B and Belsky, A and Martin, P}, title = {Photoconductivity and photoemission studies of diamond irradiated by ultrashort VUV pulses}, journal = {Applied Physics B-Lasers and Optics}, year = {2004}, volume = {78}, number = {7-8}, pages = {1001-1004}, doi = {10.1007/s00340-004-1454-1} }  "High-efficiency, simple setup for pulse cleaning at the millijoulelevel by nonlinear induced birefringence"Jullien A, Augé-Rochereau F, Chériaux G, Chambaret J-P, d'Oliveira null P, Auguste T and Falcoz F, Opt. Lett. Vol. 29(18), pp. 2184-2186. OSA - (2004). [BibTeX] [URL] BibTeX: @article{JullienOL2004, author = {Aurélie Jullien and Frédérika Augé-Rochereau and Gilles Chériaux and Jean-Paul Chambaret and Pascal d'Oliveira and Thierry Auguste and Franck Falcoz}, title = {High-efficiency, simple setup for pulse cleaning at the millijoulelevel by nonlinear induced birefringence}, journal = {Opt. Lett.}, publisher = {OSA}, year = {2004}, volume = {29}, number = {18}, pages = {2184--2186}, url = {http://ol.osa.org/abstract.cfm?URI=ol-29-18-2184} }  "Optimization of Attosecond Pulse Generation"Mairesse Y, de Bohan A, Frasinski LJ, Merdji H, Dinu LC, Monchicourt P, Breger P, Kovacev M, Auguste T, Carré B, Muller HG, Agostini P and Salières P, Phys. Rev. Lett., Vol. 93(16), pp. 163901. American Physical Society - Oct, (2004). [BibTeX] [DOI] BibTeX: @article{MairessePRL2004, author = {Mairesse, Y. and de Bohan, A. and Frasinski, L. J. and Merdji, H. and Dinu, L. C. and Monchicourt, P. and Breger, P. and Kovacev, M. and Auguste, T. and Carré, B. and Muller, H. G. and Agostini, P. and Salières, P.}, title = {Optimization of Attosecond Pulse Generation}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {2004}, volume = {93}, number = {16}, pages = {163901}, doi = {10.1103/PhysRevLett.93.163901} }  "Manipulating intense XUV coherent light in the temporal domain"Merdji H, Hergott J, Kovacev M, Priori E, Salières P and Carré B, Laser And Particle Beams., Vol. 22(3), pp. 275-278 - SEP, (2004). [BibTeX] [DOI] BibTeX: @article{MerdjiLPB2004, author = {Merdji, H and Hergott, JF and Kovacev, M and Priori, E and Salières, P and Carré, B}, title = {Manipulating intense XUV coherent light in the temporal domain}, journal = {Laser And Particle Beams}, year = {2004}, volume = {22}, number = {3}, pages = {275-278}, doi = {10.1017/S0263034604223102} }  "Characterization of collisionally pumped optical-field-ionization soft X-ray lasers"Mocek T, Sebban S, Bettaibi I, Upcraft L, Balcou P, Breger P, Zeitoun P, Le Pape S, Ros D, Klisnick A, Carillon A, Jamelot G, Rus B and Wyart J, Applied Physics B-Lasers and Optics., Vol. 78(7-8), pp. 939-944 - MAY, (2004). [BibTeX] [DOI] BibTeX: @article{MocekAPB2004, author = {Mocek, T and Sebban, S and Bettaibi, I and Upcraft, LM and Balcou, P and Breger, P and Zeitoun, P and Le Pape, S and Ros, D and Klisnick, A and Carillon, A and Jamelot, G and Rus, B and Wyart, JF}, title = {Characterization of collisionally pumped optical-field-ionization soft X-ray lasers}, journal = {Applied Physics B-Lasers and Optics}, year = {2004}, volume = {78}, number = {7-8}, pages = {939-944}, doi = {10.1007/s00340-004-1436-3} }  "Free electron laser and microwave instability interplay in a storage ring"Orlandi GL, Bruni C, Garzella D, Couprie M-E, Thomas C, Bartolini R, Rippon C and Dattoli G (2004), Phys. Rev. ST Accel. Beams., Vol. 7(6), pp. 060701. American Physical Society - Jun, (2004). [BibTeX] [DOI] BibTeX: @article{OrlandiPRSTAB2004, author = {Orlandi, G. L. and Bruni, C. and Garzella, D. and Couprie, M.-E. and Thomas, C. and Bartolini, R. and Rippon, C. and Dattoli, G.}, title = {Free electron laser and microwave instability interplay in a storage ring}, journal = {Phys. Rev. ST Accel. Beams}, publisher = {American Physical Society}, year = {2004}, volume = {7}, number = {6}, pages = {060701}, doi = {10.1103/PhysRevSTAB.7.060701} }  "Interaction of an intense laser field with a dielectric containing metallic nanoparticles"Quéré F, Grua P, Bercegol H, Martin P, Morreeuw J and Rullier J, Applied Physics B-Lasers and Optics., Vol. 78(7-8), pp. 825-828 - MAY, (2004). [BibTeX] [DOI] BibTeX: @article{QuereAPB2004, author = {Quéré, F and Grua, P and Bercegol, H and Martin, P and Morreeuw, JP and Rullier, JL}, title = {Interaction of an intense laser field with a dielectric containing metallic nanoparticles}, journal = {Applied Physics B-Lasers and Optics}, year = {2004}, volume = {78}, number = {7-8}, pages = {825-828}, doi = {10.1007/s00340-004-1437-2} }  "Intense-Laser-Field Ionization of Molecular Hydrogen in the Tunneling Regime and Its Effect on the Vibrational Excitation of H2+"Urbain X, Fabre B, Staicu-Casagrande EM, de Ruette N, Andrianarijaona VM, Jureta J, Posthumus JH, Saenz A, Baldit E and Cornaggia C, Phys. Rev. Lett.,Vol. 92(16), pp. 163004. American Physical Society - Apr, (2004). [BibTeX] [DOI] BibTeX: @article{UrbainPRL2004, author = {Urbain, X. and Fabre, B. and Staicu-Casagrande, E. M. and de Ruette, N. and Andrianarijaona, V. M. and Jureta, J. and Posthumus, J. H. and Saenz, A. and Baldit, E. and Cornaggia, C.}, title = {Intense-Laser-Field Ionization of Molecular Hydrogen in the Tunneling Regime and Its Effect on the Vibrational Excitation of H2+}, journal = {Phys. Rev. Lett.}, publisher = {American Physical Society}, year = {2004}, volume = {92}, number = {16}, pages = {163004}, doi = {10.1103/PhysRevLett.92.163004} }  "A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam"Zeitoun P, Faivre G, Sebban S, Mocek T, Hallou A, Fajardo M, Aubert D, Balcou P, Burgy F, Douillet D, Kazamias S, de Lacheze-Murel G, Lefrou T, le Pape S, Mercere P, Merdji H, Morlens A, Rousseau J and Valentin C, Nature.,Vol. 431(7007), pp. 426-429 - SEP 23, (2004). [BibTeX] [DOI] BibTeX: @article{ZeitounNat2004, author = {Zeitoun, P and Faivre, G and Sebban, S and Mocek, T and Hallou, A and Fajardo, M and Aubert, D and Balcou, P and Burgy, F and Douillet, D and Kazamias, S and de Lacheze-Murel, G and Lefrou, T and le Pape, S and Mercere, P and Merdji, H and Morlens, AS and Rousseau, JP and Valentin, C}, title = {A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam}, journal = {Nature}, year = {2004}, @article{HeppnerAPL1985, author = {Heppner, J. and Kuhl, J.}, title = {Intracavity chirp compensation in a colliding pulse mode-locked laser using thin-film interferometers}, journal = {Applied Physics Letters}, year = {1985}, volume = {47}, pages = {453-455}, doi = {10.1063/1.96144} } volume = {431}, number = {7007}, pages = {426-429}, doi = {10.1038/nature02883} }  "Few-cycle laser pulses tested with double ionization of H2"Bondoux C and Cornaggia C, Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 40(23), pp. 4463-4470 - (2004). [Abstract] [BibTeX] [URL] Abstract: Different compression schemes for the production of sub-10 fs laser pulses are tested using double ionization of H2. Compression schemes differ in the laser beam guiding modes which are necessary in order to get a spatially-homogeneous spectral broadening through self-phase modulation in argon. Guiding may take place in a hollow fibre waveguide or may be self-induced in a filament. We tested four set-ups: a single hollow fibre, two hollow fibres, a hollow fibre then a filament, and two filaments. The shortest pulses around 8 fs were recorded with the set-ups involving one or two filaments. Double ionization of H2 and the associated proton spectra give results in good agreement with the spectral and interferometric autocorrelation measurements. The two-filament set-up gives the shortest pulses. In addition, the H2 experiment reveals that the spectral phase induced with two filaments cannot be fully compensated with second-order chirped mirrors as for the other tested set-ups. BibTeX: @article{BondouxJPB2004, author = {C Bondoux and C Cornaggia}, title = {Few-cycle laser pulses tested with double ionization of H2}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2007}, volume = {40}, number = {23}, pages = {4463-4470}, url = {http://stacks.iop.org/0953-4075/40/4463} } `
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