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5 sujets IRAMIS/LIDYL

Dernière mise à jour : 14-08-2022


 

Attosecond pulses with orbital angular momentum for the detection of helicoidal dichroisms

SL-DRF-22-0244

Research field : Optics - Laser optics - Applied optics
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Attophysique (ATTO)

Saclay

Contact :

Thierry Ruchon

Starting date : 01-09-2022

Contact :

Thierry Ruchon
CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Thesis supervisor :

Thierry Ruchon
CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

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

Laboratory link : https://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 light-matter interaction in the highly nonlinear regime with angular momenta involved 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 at http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Development and applications of a laser-driven particle source

SL-DRF-22-0548

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Sandrine DOBOSZ DUFRÉNOY

Starting date : 01-10-2022

Contact :

Sandrine DOBOSZ DUFRÉNOY
CEA - DRF/IRAMIS/LIDyL/PHI

01.69.08.63.40

Thesis supervisor :

Sandrine DOBOSZ DUFRÉNOY
CEA - DRF/IRAMIS/LIDyL/PHI

01.69.08.63.40

Personal web page : https://iramis.cea.fr/LIDYL/Phocea/Pisp/index.php?nom=sandrine.dobosz

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

Laser-plasma accelerators have demonstrated their great potential for more than 20 years, and it is now possible to accelerate electrons from a few MeV up to several GeV over only a few centimeters. Progress realized in this domain, following technological advances in lasers, open the door to the applications. These pulsed sources exhibit unique properties: 1 / their compactness is a major asset for designing the next generation of accelerators for high energy physics. 2 / the ultra-short duration (a few femtoseconds) of the particle bunch allows to reach extremely high dose rates, particularly interesting for radiotherapy (flash effects).



The candidate will have to implement the most innovative techniques to develop a laser-plasma electron source suitable for selected applications, in particular, to study the physicochemical effects resulting from the related high dose rate and relativistic energy. The project will extend to experiments carried out in collaboration with biologists to test the interest of such particle sources on living cells for the treatment of cancer with flash radiotherapy.
Attosecond imaging of electronic wavepackets in molecular gases

SL-DRF-22-0460

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Attophysique (ATTO)

Saclay

Contact :

Hugo MARROUX

Pascal SALIERES

Starting date : 01-10-2022

Contact :

Hugo MARROUX
CEA - DRF/IRAMIS/LIDyL/ATTO

0169081744

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 :



The student will first generate XUV attosecond pulses using an intense Titanium:Sapphire laser (ATTOLab Excellence Equipment). These ultrashort pulses will then be used to investigate the ionization dynamics of molecular gases: electron ejection, electronic rearrangements in the ion, charge migration, quantum decoherence…



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]. In order to generate isolated pulses, it is necessary to confine the generation in an ultrashort temporal window, which implies the development of various optical manipulation techniques.



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? How does the electronic cloud rearrange? What amount of quantum entanglement is created by photoionization? These questions are currently “hot topics” because time-resolved experimental observations are now feasible. In particular, it is now possible not only to measure in real time the buildup of a resonance [2], but also to reconstruct the 3D movie of electron ejection [3].



The objective of the thesis is first to generate attosecond pulses with duration and central frequency adequate for the excitation of various molecular systems. The objective is then to measure the instant of appearance and the angular distribution of the charged particles, electrons and ions. These spatial and temporal informations will allow the reconstruction of the full 3D movie of the electron ejection, as well as of the hole migration in the ion leading to fragmentation. Finally, quantum decoherence, e.g., induced by ion-photoelectron entanglement, will be studied using a new technique recently demonstrated in our laboratory [4].



The experimental work will include the development and operation of a setup installed on the FAB1 laser of the ATTOLab Excellence Equipment allowing: i) the generation of attosecond XUV radiation, ii) its characterization using quantum interferometry, iii) its use in photo-ionization spectroscopy. 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 and European laboratories through joint experiments in the different associated laboratories (Lund, Milano).



References :

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

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

[3] A. Autuori, et al., arXiv:2107.13990v1 (2021)

[4] C. Bourassin-Bouchet, et al., Phys. Rev. X 10, 031048 (2020)
Attosecond spectroscopy of circular and helicoidal magnetic dichroisms and of their inverses

SL-DRF-22-0901

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Attophysique (ATTO)

Saclay

Contact :

Thierry Ruchon

Starting date : 01-10-2022

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 : https://iramis.cea.fr/LIDYL/ATTO/

More : https://iramis.cea.fr/LIDYL/DICO/

Attosecond sources are a unique spectroscopic tool which emit light in the extreme ultraviolet (XUV) with extremely short durations (1as=10-18s). These sources are based on high harmonic generation (HHG) of an intense femtosecond laser and allow to study light-matter interactions with superb precision, both for fundamental and applied matters. Our laboratory pioneered the developement, control and shaping of these attosecond XUV sources. In the last few years, we established how the angular momenta of attosecond pulses can be controlled, and now have sufficiently mature sources to envision their spectroscopic applications.



During this thesis, we will develop original magnetic dichroism experiments using attosecond pulses. With the spin angular momentum and orbital angular momentum of the pulses, we will probe the circular and helicoidal magnetic dichroism of magnetic samples. This will give access to photoinduced spin dynamics, either for homogeneous systems or for systems hosting magnetic singularities. On the one hand, we will explore the fundamental aspects of the light-matter interaction in the ultra short regime in the presence of angular momentum. On the other hand, we will attempt to comprehend spin dynamics hitherto unexplored. Finally, we will explore the possibility of transiently modifying the magnetization of materials with laser pulses, through inverse phenomena such as the inverse Faraday effect or inverse helicoidal dichroism.



L’étudiant(e) acquerra une pratique de l’optique des lasers, en particulier femtoseconde, et de la spectroscopie ultrarapide en matière condensée. Il (elle) étudiera également les processus de physique des champs forts sur lesquels se basent la génération d'harmonique élevées. Il/elle deviendra un(e) experte de la physique attoseconde. L’acquisition de techniques d’analyse approfondie, d’interfaçage d’expérience seront encouragées même si non indispensables.



The student will acquire practical knowledge about lasers, in particular femtosecond lasers, and of time resolved spectroscopy of condensed matter, especially magnetic materials. 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 at http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Doppler-boosted lasers: a new path to extreme QED pair plasmas in light-matter and light-quantum vacuum interactions

SL-DRF-22-0858

Research field : Theoretical Physics
Location :

Service Laboratoire Interactions, Dynamique et Lasers (LIDyL)

Physique à Haute Intensité (PHI)

Saclay

Contact :

Henri VINCENTI

Starting date : 01-10-2022

Contact :

Henri VINCENTI
CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Thesis supervisor :

Henri VINCENTI
CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

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

Laboratory link : https://iramis.cea.fr/lidyl/phi/

How does light interact with matter or the quantum vacuum at intensities where the physics is governed by Quantum Electrodynamics (QED)? What are the properties of the QED electron-positron pair plasma produced in those interactions? Can the probing of this plasma help address open problems in quantum field theory and astrophysics? Answering these questions requires light intensities far beyond the ones achieved by the most intense PetaWatt (PW) laser on earth. To break this barrier, we propose new schemes to considerably ‘boost’ the intensity of present lasers by Doppler effect employing physical systems called ‘relativistic plasma mirrors’.



When interacting with matter or the quantum-vacuum, a Doppler-boosted laser can convert its energy into cascades of \gamma-photons and e-/e+ pairs via strong-field QED (SF-QED) processes. As the intense boosted fields can be focused over small spatial scales (<50nm), they can lead to relativistic pair plasma states of extreme densities (>>1028cm-3). Such QED plasmas, which are currently out of the reach of conventional means, have so far been terra incognita in simulations and experiments. Their probing could have a major impact on the test of QED in uncharted regimes, potentially revealing properties of quantum fields beyond the standard model. It could also help elucidate the precise nature of the emission behind extreme astrophysical objects (e.g., gamma-ray bursts) where QED pair plasmas are expected to play a leading role.



This PhD project will use theory and exascale simulations to devise schemes employing Doppler-boosted beams to probe novel QED plasma states in light-matter and light-quantum vacuum interactions. Exascale simulation tools will be developed to understand the basic physics of these QED plasmas and help identify clear SF-QED signatures that shall be observed in experiments. Simulations will be key to stimulate, design and guide experiments intended to detect these signatures at PW laser facilities.

 

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