Missions

The Laboratoire d'Optique Appliquée, located on the École Polytechnique campus in Palaiseau, is hiring a postdoctoral researcher to pursue the development of high repetition rate laser-plasma acceleration. The postdoctoral researcher will join the APPLI team and collaborate with the PCO team on Ytterbium laser technology. The main responsibilities will be as follows:
- Development of the 100 Hz accelerator in LAPLACE, along with a small team of engineers, students and researchers. Perform first electron acceleration experiment at 100 Hz, characterize and optimize electron beam properties. Demonstrate high quality electron beams and robustness of the accelerator.
- Set-up proof-of-principle experiments for electron acceleration driven by post-compressed Ytterbium laser technology. Demonstrate and characterize first electron beams in these experiments.

Activities

- Take part in laser-plasma acceleration experiments on the LAPLACE platform (main task). This includes getting hands-on with the experiment, conducting the experiments, acquiring data, and analyzing the results. High level of responsibility.
- Plan and carry out future acceleration experiments using the Ytterbium laser (main task). This includes designing the experiment, ordering and implementing the equipment, and conducting proof-of-principle experiments. High level of responsibility.
- Participate in the supervision of PhD students. Lower level of responsibility.
- Write scientific articles based on the results obtained and present results at international conferences.

Skills

You hold a PhD in Physics and have a strong interest in experimental physics with beyond state-of-the-art equipment. You have a taste for teamwork, you are able to work in collaboration with PhD students and you are not afraid of hands-on experimental work. Expertise in laser-plasma accelerators, or, at minima, in high-intensity laser-plasma interaction is required. You may also have expertise in some of the following: high intensity femtosecond lasers, particle accelerators. Experience in developing small codes (python, matlab) for data analysis. Optional: general skills in instrumentation control and man-machine interfaces (Python, Tango, Labview...) would be useful as well.

Work Context

The position is based at the Laboratoire d'Optique Appliquée, located on the École Polytechnique campus in Palaiseau, within the APPLI group led by Jérôme Faure. The research focuses on the acceleration of relativistic electrons through laser-plasma interaction, an emerging technique that enables the acceleration of electron beams via the interaction of ultra-intense lasers with underdense plasmas. The electrons are accelerated in the plasma over very short distances (millimeter) and emit X-rays by interaction with the plasma fields or laser fields. This enables electron and X-ray sources with unique characteristics: compactness, micrometric source size and femtosecond duration, which paves the way for many applications in medicine (imaging, cancer treatment), in science (physics, biology), but also for industry (non-destructive testing).

In the past few years, our team at LOA has demonstrated the first high repetition rate laser-plasma accelerator, delivering electron beams at kHz in the 5-10 MeV range. We are currently working on further developing this field by pushing the boundaries of high average power femtosecond lasers and their use for accelerating particles to multi-100's MeV at 100 Hz or more. To this end, we are pursuing two different paths:
- The first one is the LAPLACE project (Laser Plasma Acceleration Center, see https://laplace-loa.fr), a platform dedicated to laser-plasma accelerators (LPA). The objective is to develop an accelerator operating at 100 Hz and producing relativistic electrons in the energy range 20-200 MeV. The accelerator is driven by a 100 Hz Thales Ti:Sapphire laser system. The goal of LAPLACE is to bring laser-plasma acceleration to a high level of maturity (TRL 5-6) and to build a true prototype electron accelerator, whose robustness and stability will enable access to applications. The construction of the platform is currently being finalized, and the experiment will enter a commissioning phase in 2026.
- The second approach is more exploratory and relies on the use of Ytterbium (Yb) laser technology. Yb lasers can deliver very high average powers (up to kW) albeit with longer pulse duration (few-100 fs). LOA is currently developing novel pulse compression techniques based on nonlinear spectral broadening in multi-pass cells to reduce the pulse duration down to the 10-20 fs range, thus rendering it compatible with laser plasma acceleration. The idea here is to perform proof-of-principle experiments to investigate whether this laser technology is suitable for laser-plasma acceleration.

Constraints and risks

Ultra-intense lasers, ionizing radiations, compressed gases