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Accueil > Équipes scientifiques > Dynamiques et Interactions : Rayonnement, Atomes, Molécules (DIRAM) > Propriétés spectrales et temporelles des lasers XUV générés par plasma > Offres de stages, thèses, post-docs > Temporal metrology of ultra-short XUV lasers generated from plasmas

Phd proposal

Temporal metrology of ultra-short XUV lasers generated from plasmas

PhD Proposal

Description of the thesis project :

Over the last decade new coherent XUV sources (wavelength a few 10 nm) have been developed in laboratories. These sources (high-order harmonics, free-electron lasers, plasma-based XUV lasers) have unprecedented outstanding properties in terms of coherence, brightness, or pulse duration. This opens the route to exploring new scientific fields such as ultrafast dynamics of electrons in gases and solids, or non-linear interaction of X-rays with matter. In parallel with the continuing development of the sources, an important effort focuses on the (spatial, spectral, temporal) metrology of their specific characteristics, which most often requires the development of novel instruments.
Recently significant progress has been achieved in reducing the pulse duration of XUV lasers generated from hot and dense plasmas. The ultimate goal is to reach the femtosecond temporal domain, which is particularly attractive for numerous applications. Such a goal seems attainable while operating XUV lasers in the so-called seeded mode, where a high-order harmonic femtosecond pulse is injected and amplified in the plasma amplifier. Numerical simulations performed in our group as well as in other laboratories predict however that the temporal structure of the output pulse can be very complex, involving intense peaks of 10 fs duration, and strongly dependant on the amplification parameters. In order to progress in the understanding and the control of the temporal properties of the sources, benchmarking of the simulation predictions with experimental measurements is crucially needed. Since the temporal resolution of cuurently available diagnostics (streak camera) is limited to 1 ps, we need to adapt other measurement techniques, on the basis of recent developments performed for X-ray free-electron lasers.
In the frame of the OPT2X consortium funded by Université Paris-Saclay, we are now developing a new temporal diagnostic based on the so-called THz streaking technique. This technique consists in measuring the energy spectrum of photoelectrons, which are produced by ionizing rare gas atoms with the XUV pulse in the presence of a single-cycle THz pulse. The instrument under development is designed to allow a single-shot measurement of the temporal profile of the XUV pulse with femtosecond resolution. The PhD candidate will be involved in the final steps of the design of the instrument and in its commissioning (expected in late 2017). He/she will then work on its implementation and exploitation at different XUV laser beamlines, as well as possibly other types of ultrashort XUV sources. The analysis of the obtained experimental data will be supported by numerical simulations with existing numerical codes, developed in our group or by external collaborators. The project will be carried out in the frame of collaborations with several groups from Paris-Saclay laboratories, and will involve access to the two XUV laser beamlines in France (LOA in Palaiseau and LASERIX in Orsay).

Objective :

The objective of the project is to progress in the understanding and the control of injection-seeded XUV lasers through the detailed characterization of their pulse temporal structure at the femtosecond timescale.

Context :

The development of temporal diagnistics, which are both high performing and reliable, is a crucial issue for exploiting the potential of ultrashort XUV sources for a variety of emerging applications.For injection-seeded XUV lasers, one of the goal pursued by the community is to achieve femtosecond pulse duration in a controlled and reproducible way.

Method :

The project is mainly experimental involving the implementation of the new instrument (commissioning, exploitation). It also includes numerical simulation studies, with existing numerical codes, while few limited developments will be required.

Bibliography :

- Demonstration of a 2-ps transient X-ray laser
A. Klisnick, J. Kuba, D. Ros, R. Smith, G. Jamelot, C. Chenais-Popovics, R. Keenan, S. Topping, C. L. S. Lewis, F. Strati, G. J. Tallents, D. Neely, R. Clarke, J. Collier, A. G. MacPhee, F. Bortolotto, K. A. Janulewicz, P. V. Nickles
Phys. Rev A 65, 033810 (2002)

- Temporal characterization of a picosecond XUV laser pumped in grazing incidence
L Meng, AC Bourgaux, S Bastiani-Ceccotti, O Guilbaud, M Pittman, S Kazamias, K Cassou, S Daboussi, D Ros, and A Klisnick
Appl. Phys. Lett., 101 (14), 141125 (2012)

- Two-dimensional Maxwell-Bloch simulation of quasi-π-pulse amplification in a seeded XUV laser
O. Larroche and A. Klisnick
Physical Review A 88, 033815 (2013).

- Gain dynamics in quickly ionized plasma for seeded operated soft x−ray lasers
O. Guilbaud, G.V. Cojocaru, O.Delmas, R.G. Ungureanu, R.A. Banici, S. Kazamias, K.Cassou, O.Neveu, J.Demailly, E.Baynard, M. Pittman, A. Le Marec, A. Klisnick, L. Lu, Ph. Zeitoun, D. Ursescu and D. Ros
Opt. Lett. 40 (2015) 1-4

- Evidence of partial temporal coherence effects in the linear autocorrelation of extreme ultraviolet laser pulses
A. Le Marec, O. Guilbaud, O. Larroche, and A. Klisnick
Opt. Lett. 41 (2016) 3387-3390

Contact :

Annie Klisnick

annie.klisnick@u-psud.fr, +33 (0)1 69 15 76 17

Institut des Sciences Moléculaires d’Orsay,

CNRS, Université Paris-Sud, Bât. 350, Orsay, France

Deadline for application : 21 April 2017

Funding : Candidates will apply for a doctoral fellowship through EDOM Doctoral School (https://www.universite-paris-saclay.fr/en/education/doctorate/ondes-et-matiere#l-ecole-doctorale)

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