Postdoc in Flying-Focus Laser Pulses for Laser-Wakefield Acceleration, LOA (CNRS), Palaiseau, France
Job Description
This postdoc in laser-plasma acceleration is at the Laboratoire d’Optique Appliquée (LOA) near Paris. You will lead the simulation work on “flying-focus” laser pulses. These pulses have a focal point that moves through a plasma at a speed you can control, even faster than light in vacuum. The goal is to push electron beams to higher energy.
At a glance
- Position: Postdoctoral researcher, fixed-term contract (CNRS offer UMR7639-LUCROV-002)
- Where: LOA, École Polytechnique campus, Palaiseau (Essonne), France
- Group: Ultrafast Sources of Particles and X-rays (UPX)
- Pay: €3,131 to €4,341 gross a month, depending on experience
- Duration: 24 months, full time; planned hire date 1 February 2027
- Apply: 1 November 2026 at 00:00 (Paris time), so submit by 31 October
About the laser-plasma acceleration project
- Build and run particle-in-cell (PIC) and optical-propagation simulations of flying-focus pulses in plasma
- Focus on ultrashort pulses in the sub-10 femtosecond range
- Explore spatio-temporal pulse shapes that tune the focal line’s position, duration or intensity
- Use those shapes to improve electron injection, acceleration or X-ray generation
- Develop analytical models of the laser-plasma interaction
- Work with the experimental teams on 100 TW-class and petawatt lasers, and compare simulations with data
- Write papers and present at conferences
Some background helps. In a laser-wakefield accelerator, electrons slowly outrun the accelerating part of the plasma wave. This limits how far they gain energy. The flying-focus idea avoids that. It combines an axiparabola, a mirror that focuses each ring of the beam at a different distance, with a controlled delay across the beam.
Why this role matters
Laser-plasma accelerators can reach fields above 100 GV/m. That could shrink parts of an accelerator from kilometres to centimetres. Beating the dephasing limit is one of the main open problems. The simulations in this project will guide real experiments on some of Europe’s strongest lasers.
What CNRS is looking for
- A PhD in Physics, with a strong interest in plasma simulation
- Prior experience with laser-plasma simulation, especially particle-in-cell codes
- Expertise in at least one of: laser-plasma accelerators, high-intensity lasers, laser-plasma interaction or optics
- Ability to work in a team and to coordinate with PhD students
- Good spoken and written English for papers and international talks
Pay and location
The CNRS portal gives €3,131 to €4,341 gross a month, set by experience. The offer lists 44 days of annual leave (leave plus RTT days). CNRS pays 75% of public transport costs. The post is in a protected research sector (PPST). Your arrival must be approved by the French research ministry (MESR) before you start, so allow time for that check.
How to apply
Apply through the official CNRS page. The closing date is 1 November 2026 at 00:00 (Paris time), so submit by 31 October. Send a CV with your publication and conference list, and a cover letter.
See all our postdoc jobs, or browse more research jobs on ResearchJobs.in.
Hiring institution: Laboratoire d'Optique Appliquée (LOA), CNRS
Official advertisement: emploi.cnrs.fr
How to prepare for this application
- Prepare a short summary of your PIC work: which code (for example WarpX, FBPIC, Smilei or OSIRIS), grid choices and run sizes
- Revise dephasing, pump depletion and injection in laser-wakefield acceleration, with the key scaling laws
- Read recent papers on axiparabolas, flying focus and spatio-temporal couplings, so you can discuss them
- Think about how you would compare a simulation with an experiment, and which diagnostics matter most
- Plan for the PPST security approval: have your CV, passport and degree details ready early
About LOA and CNRS
The Laboratoire d'Optique Appliquée (UMR 7639) is a joint research unit of CNRS, École Polytechnique and ENSTA Paris. It sits on the École Polytechnique campus in Palaiseau, within the Institut Polytechnique de Paris. It works on ultrafast science, intense femtosecond lasers and compact sources of particles and X-rays. See the UPX group page. CNRS is France's national research organisation.
