In a laser-plasma accelerators, a very intense laser pulse is focused into a gas and creates a fully ionized plasma in a few femtoseconds. The laser pulse then drives a plasma wakefield which accelerates electron bunches with femtosecond duration. The electron beam is, in principle, perfectly synchronized with the laser (jitter-free) which is a great advantage for performing pump-probe experiments with unprecedented resolutions.

Developing a kHz laser-plasma accelerators relies on the use of a kHz laser. We use the Salle Noire laser at LOA which delivers 3 mJ pulse at kHz in only 3.5 fs, i.e. in a single light cycle ! These extreme pulse durations allow us to reach the laser intensity that is necessary to drive a large wakefield for accelerating electrons.

We have been developing this experiment for the past five years thanks to an ERC grant (FEMTOELEC). Our accelerator has currently reached a high level of reliability and delivers routinely electrons beams with few MeV electrons and charge in the 1-10 pC range.

Our current projects are focusing on:

• Physics: optimization of the injection process in the accelerator. Role of the absolute phase (CEP) in the injection and acceleration process
• Technology: developments of feed-back loops, control systems and differential pumping schemes for running our experiment like an accelerator
• Applications: (i) in condensed matter by performing time-resolved electron diffraction experiments, (ii) in radio-biology by doing femtosecond irradiation of biological cells…

Related publications:

“Demonstration of stable long-term operation of a kilohertz laser-plasma accelerator”; L. Rovige et al., submitted (2020)

“A review of recent progress on laser-plasma acceleration at kHz repetition rate” ; J. Faure, D. Gustas, D. Guénot, A. Vernier, F. Böhle, M. Ouillé, S. Haessler, R. Lopez-Martens and A. Lifchitz, Plasma Physics Controlled Fusion 61, 014012 (2019)

“High-charge relativistic electron bunches from a kHz laser-plasma accelerator”; D. Gustas, D. Guénot, A. Vernier, S. Dutt, F. Böhle, R. Lopez Martens, A. Lifschitz and J. Faure, Phys. Rev. Acc. & Beams 21, 013401 (2018)

“Relativistic electron beams driven by kHz single-cycle light pulses”; D. Guénot, D. Gustas, A. Vernier, B. Beaurepaire, F. Böhle, M. Bocoum, M. Lozano, A. Jullien, R. Lopez-Martens, A. Lifschitz and J. Faure, Nature Photonics 11, 293 (2017)