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PhD subjects

7 sujets IRAMIS

Dernière mise à jour : 23-06-2018


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• Radiation-matter interactions

 

High energy chemistry ; Impact of inner shell ionizations on biological molecules

SL-DRF-18-0325

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Marie-Anne Hervé du Penhoat

Starting date : 01-09-2018

Contact :

Jean-Philippe RENAULT

CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Marie-Anne Hervé du Penhoat

UPMC - IMPMC

+33 1 44 27 72 05

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

The aim of this PhD project is to understand the chemical effects of inner shell ionizations. Indeed such ionizations that inject hundreds of eV in biomolecules can have important radiobiological consequences, but the mechanisms leading to biomolecule damages remain to be deciphered.



We will carry on irradiation of water and solutions of biological molecules in water using soft X rays produced by SOLEIL synchrotron. New spectroscopic techniques sensitive to changes in the biological molecules upon irradiation will also be investigated. These data will be compared to ab initio molecular dynamics calculations.

Attosecond XUV pulses carrying an angular momentum: synthesis and novel spectroscopies

SL-DRF-18-0221

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Thierry RUCHON

Starting date : 01-09-2018

Contact :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Thesis supervisor :

Thierry RUCHON

CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Personal web page : http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

Light in the extreme ultraviolet (XUV) is a universal probe of mater, may it be in diluted or condensed phase: photons associated with this spectral range carry energy of 10 to 100 eV, sufficient to directly ionize atoms, molecules or solids. Large scale instruments such as synchrotrons or the lately developed free electron lasers (FEL) work in this spectral range and are used to both study fundamental light matter interaction and develop diagnosis tools. However these instruments do not offer the temporal resolution require to study light matter interactions at their ultimate timescales, which is in the attosecond range (1as = 10^-18s). An alternative is offered by the recent development of XUV sources based on high order harmonic generation (HHG). They are based on the extremely nonlinear interaction of a femtosecond intense laser beam with a gas target. Our laboratory has pioneered the development, control and design of these sources providing XUV attosecond pulses.



During this PhD project, we will develop specific setups to allow these attosecond pulse to carry angular momenta, may it be spin or orbital angular momenta. This will open new applications roads through the observations of currently ignored spectroscopic signatures. On the one hand, the fundamental aspects of the coupling of spin and orbital angular momentum of light in the highly nonlinear regime will be investigated, and on the other hand, we will tack attosecond novel spectroscopies, may it be in diluted or condensed phase. In particular, we will chase helical dichroism, which manifest as different absorptions of beams carrying opposite orbital angular moments. These effects are largely ignored to date.



The student will acquire practical knowledge about lasers, in particular femtosecond lasers, and hands on spectrometric techniques of charged particles. He/she will also study strong field physical processes which form the basis for high harmonic generation. He/she will become an expert in attosecond physics. The acquisition of analysis skills, computer controlled experiments skills will be encouraged although not required.

Full subject available at http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/.

UV-induced processes in guanine quadruplexes studied by time-resolved optical spectroscopy: from photon absorption to radical reactivity

SL-DRF-18-0975

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Dimitra MARKOVITSI

Starting date : 01-09-2018

Contact :

Dimitra MARKOVITSI

CNRS - LIDYL

0033169084644

Thesis supervisor :

Dimitra MARKOVITSI

CNRS - LIDYL

0033169084644

Personal web page : http://iramis.cea.fr/Pisp/18/dimitra.markovitsi.html

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=575

Guanine Quadruplexes (G4) are four-stranded structures formed by guanine rich DNA sequences. They have been correlated with the oxidative damage which perturbs biological functions. In addition, G4 structures are studied in respect to their applications in molecular electronics and nanotechnologies.

The objective of the thesis is to study the generation and the reactivity of guanine radicals (including electron holes, important in charge transport) induced by absorption low energy UV radiation by G4. The investigation will involve the use of several experimental and computational techniques:

o The electrons ejected by photo-ionization and the resulting base radicals will be studied by time-resolved absorption spectroscopy and time-resolved circular dichroism, from nanoseconds to milliseconds.

o The dynamics of the excited states, expected to play a role in the photo-ionization process, will be studied by fluorescence spectroscopy, from femtoseconds to nanoseconds.

o The observed optical spectra will be interpreted by means of quantum chemistry methods.

o The reaction products resulting from UV-induced radicals will be identified using analytical methods.

Fast and innovative understanding of ageing processes in lithium-ion batteries by radiolysis

SL-DRF-18-0424

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l'Energie

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Sophie LE CAER

Starting date : 01-09-2018

Contact :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Thesis supervisor :

Sophie LE CAER

CNRS - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 58

Personal web page : iramis.cea.fr/Pisp/sophie.le-caer

Laboratory link : http://iramis.cea.fr/nimbe/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=50

Ageing and safety issues are a critical challenge for lithium-ion batteries. Recently we have demonstrated for the first time that radiolysis (i.e. the chemical reactivity induced by the interaction between ionizing radiation and matter) is a powerful tool for a short-time (minutes-days) identification of the by-products arising from the degradation of the electrolyte of a lithium-ion battery, after several weeks or months of cycling.



The aim of the present PhD thesis is to extend the radiolysis approach to:

* screen electrolytes and combinations of electrolyte and active materials to identify the most robust ones. Reaction mechanisms induced by ionizing radiation will be studied in details for the most promising electrolytes identified;

* study carefully the interfacial processes (electrode/electrolyte) with negative and positive électrodes for the most interesting systems previously identified.



A global and detailed picture of reaction mechanims at stake in lithium-ion batteries will thus be provided. Moreover, the systems; which are the most robust towards ionizing radiation and thus to electrolysis, will be identified and carefully studied.

Tunable attosecond pulses for the study of photoionization dynamics

SL-DRF-18-0844

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Pascal SALIERES

Starting date : 01-10-2018

Contact :

Pascal SALIERES

CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Thesis supervisor :

Pascal SALIERES

CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Personal web page : http://iramis.cea.fr/Pisp/pascal.salieres/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

More : http://attolab.fr/

Summary :



Using tunable attosecond pulses produced with an optical parametric amplifier (OPA) pumped by an intense Titanium:Sapphire laser (ATTOLab Excellence Equipment), the student will investigate the ionization dynamics of atomic and molecular gases close to resonances. The objective is to follow in real time the electron ejection and to measure the buildup of the resonance profile.



Detailed summary :



Recently, the generation of sub-femtosecond pulses, so-called attosecond pulses (1 as=10-18 s), has made impressive progress. These ultrashort pulses open new perspectives for the exploration of matter at unprecedented timescale. Their generation result from the strong nonlinear interaction of short intense infrared (IR) laser pulses (~20 femtoseconds) with atomic or molecular gases. High order harmonics of the fundamental frequency are produced, covering a large spectral bandwidth in the extreme ultraviolet (XUV) range. In the temporal domain, this coherent radiation forms a train of 100 attosecond pulses [1].



With such attosecond pulses, it becomes possible to investigate the fastest dynamics in matter, i.e., electronic dynamics that occur naturally on this timescale. Attosecond spectroscopy thus allows studying fundamental processes such as photo-ionization, in order to answer questions such as: how long does it take to remove one electron from an atom or a molecule? More precisely: how long does it take for an electron wavepacket produced by absorption of an attosecond pulse to exit the atomic/molecular potential? The measurement of such tiny ionization delays is currently a “hot topic” in the scientific community. In particular, the study of the ionization dynamics close to resonances would give access to detailed information on the atomic/molecular structure, such as the electronic rearrangements in the remaining ion upon electron ejection. Recently, we have studied an auto-ionizing resonance, so-called “Fano resonance”. We have shown through 2-photon XUV+IR ionization that it is possible to observe in real time the buildup of the resonance profile [2].



The objective of the thesis is to generalize the technique to the study of other types of atomic/molecular resonances, such as shape resonances. To this end, tunable attosecond pulses will be generated using the mid-IR [1.2-2µm] radiation from an optical parametric amplifier (OPA) pumped by an intense Titanium:Sapphire laser. Finally, the measurement of the photoelectron angular distribution, in combination with the temporal information detailed above, will allow the reconstruction of the full 3D movie of the electron ejection.

The experimental work will include the operation of a setup installed in the FAB1 laser of ATTOLab allowing: i) the generation of attosecond XUV radiation, ii) its characterization using quantum interferometry, iii) its use in photo-ionization spectroscopy (electron detection). The theoretical aspects will also be developed. The student will be trained in ultrafast optics, atomic and molecular physics, quantum chemistry, and will acquire a good mastery of charged particle spectrometry. A background in ultrafast optics, nonlinear optics, atomic and molecular physics is required.

Part of this work will be performed in collaboration with partner French laboratories (ANR CIMBAAD) and members of the MEDEA European Network through joint experiments in the different associated laboratories (Milano, Lund).



References :

[1] Y. Mairesse, et al., Science 302, 1540 (2003)

[2] V. Gruson, et al., Science 354, 734 (2016)

Plasma mirrors on-chip : “towards extreme intensity light sources and table-top particle accelerators”

SL-DRF-18-0432

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Physique à Haute Intensité

Saclay

Contact :

Henri VINCENTI

Guy BONNAUD

Starting date : 01-10-2018

Contact :

Henri VINCENTI

CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Thesis supervisor :

Guy BONNAUD

CEA - DRF/IRAMIS/LIDyL/PHI

0169088140

Personal web page : http://iramis.cea.fr/Pisp/henri.vincenti/

Laboratory link : http://iramis.cea.fr/LIDYL/PHI/

More : https://www.picsar.net

With the advent of PetaWatt (PW) class lasers capable of achieving light intensities of 10^22W.cm-2 at which matter turns into a plasma, Ultra-High Intensity (UHI) physics now aims at solving two major challenges: can we produce high-charge compact particle accelerators with high-beam quality that will be essential to push forward the horizons of high energy science? Can we reach extreme light intensities approaching the Schwinger limit 10^29W.cm-2, beyond which light self-focuses in vacuum and electron-positrons pairs are produced? Solving these major questions with the current generation of high-power lasers will require conceptual breakthroughs that will be developed during this PhD.



In particular, the goal of this PhD proposal is to demonstrate that so-called ‘relativistic plasma mirrors’, produced when a high-power laser hits a solid target, can provide simple and elegant paths to solve these two challenges.  Upon reflection on a plasma mirror surface, lasers can produce high-charge relativistic electron bunches and bright short-wavelength attosecond harmonic beams. Could we use plasma mirrors to tightly focus harmonic beams and reach extreme light intensities, potentially approaching the Schwinger limit? Could we employ plasma mirrors as high-charge electron injectors in a PW laser capable of delivering accelerating gradients of 100TV.m-1, or in a laser wakefield accelerator, to build ultra-compact particle accelerators?



The mission of the PhD candidate will be to answer these two interrogations ‘on-chip’ using massively parallel simulations on the largest supercomputers in the world. To this end, the successful candidate will make use of our recent transformative developments in ‘first principles’ Particle-In-Cell (PIC) simulations of UHI laser-plasma interactions that enabled the 3D modelling of plasma mirror sources with high-fidelity on current petascale and future exascale supercomputers. These developments were recently implemented, validated and tested in our code PICSAR (https://www.picsar.net). Armed with PICSAR, the candidate will model novel schemes employing plasma mirrors to address the two UHI challenges introduced above.

Spatio-temporal control of high harmonic generation in semiconductors for attosecond pulse emission

SL-DRF-18-0961

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Willem Boutu

Hamed MERDJI

Starting date : 01-10-2018

Contact :

Willem Boutu

CEA - DRF/IRAMIS/LIDYL/ATTO

0169085163

Thesis supervisor :

Hamed MERDJI

CEA - DRF/IRAMIS/LIDyL/ATTO

0169085163

Personal web page : http://iramis.cea.fr/LIDYL/en/Phocea/Pisp/index.php?nom=willem.boutu

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=1149

Ultrafast nano-photonics science is emerging thanks to the extraordinary progresses in nano-fabrication and ultrafast laser science. Boosting extremely intense electric fields in nano-structured photonic devices has the potential of creating nano-localized sources of energetic photons or particles opening vast applications in science and in the industry. Optoelectronic is extending to the highly non-linear regime. A recent impact of this capability of controlling the response of above band gap electrons under strong fields is the emergence of high harmonic generation (HHG) in crystal [1-6]. 2D and 3D semiconductors exhibits properties of high electron mobility that allows to drive intense electrons currents coherently in the conduction band. HHG are emitted when those electrons recombine to the valence band. This is a pure above band gap non-perturbative phenomena which occurs efficiently in a few 10s to 100s nanometer exit layer of a crystal and down to an atomically thin layer [5,6]. The strong electron current from which HHG originate can be manipulated in space and time. The project will focus in the strong localization in space, and time, at the single optical cycle scale [7,8], of the harmonic generation process. This control can not only revolutionize attosecond science but also prepare a new generation of ultrafast visible to X-ray opto-electronic devices. Based on the CEA group expertise, experimental and theoretical resources [9-12], the fellow will seek for efficient ways to boost the interaction regime through plasmonic amplification and field confinement for the generation of nanoscale, attosecond high harmonic sources in semiconductors. A specific focus will be on 2D materials like graphene, MoS2 and h-BN. Attosecond pulse generation will also be investigated by using harmonic phase measurements available at CEA (RABBITT, FROG techniques). We will also develop an original nanostructured sample that will allow to generate an attosecond light house inside the semiconductor to isolate single attosecond burst of light.

The research will take place in NanoLight facility, a brand new lab equipped with two laser sources: a 100kHz few optical cycles mid-infrared intense OPCPA (tunable from 1,5 to 3.4 µm wavelength) and a 2µm intense MHz rep/rate few optical cycles fiber laser and and ATTOLAB facility equipped with CEP stable Ti:Sa lasers and attosecond metrology.

1. Ghimire, S. et al. Observation of high-order harmonic generation in a bulk crystal. Nat. Phys. 7, 138–141 (2011).

2. Luu, T. T. et al. Extreme ultraviolet high-harmonic spectroscopy of solids. Nature 521, 498–502 (2015).

3. Ndabashimiye, G. et al. Solid-state harmonics beyond the atomic limit. Nature 534, 520–523 (2016).

4. You, Y. S., et al. Anisotropic high-harmonic generation in bulk crystals. Nat. Phys. 13, 345–349 (2017).

5. Liu H. et al. High-harmonic generation from an atomically thin semiconductor. Nature Physics 13, 262–265 (2017).

6. Yoshikawa, N., et al. High-harmonic generation in graphene enhanced by elliptically polarized light excitation. Science, 356, 736-738 (2017).

7. Hohenleuter, M. et al. Real-time observation of interfering crystal electrons in high-harmonic generation. Nature 523, 572-575 (2015).

8. Langer, F. et al., Lightwave-driven quasiparticle collisions on a subcycle timescale. Nature 533, 225–229 (12 May 2016).

9. Franz et al. submitted to Science Advances arXiv:1709.09153

10. Shaaran, T et al. Nano-Plasmonic near Field Phase Matching of Attosecond Pulses. Scientific Reports 2017, 7, 6356.

11. Shi, L. et al. Self-Optimization of Plasmonic Nanoantennas in Strong Femtosecond Fields. Optica 2017, 4, 1038–1043.

12. Nicolas R. et al. Plasmon-Amplified Third Harmonic Generation in metal/dielectric resonators, submitted to ACS Nano (2017).

 

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