Laser-plasma acceleration with diffraction free and Tunable- Group Velocity laser pulses – TGV

Laser-Plasma Accelerators (LPAs) have the capability to produce electric fields exceeding 100 GV/m, that is about three orders of magnitude larger than those obtained by conventional radio-frequency accelerators. They could thus allow for a drastic decrease of the size of accelerators for scientific, medical and industrial applications. Their extreme field gradients make also of LPAs promising candidates for future high energy colliders.
The objective of the project is to explore novel laser-plasma coupling concepts for increasing the energy of stable and high-quality electron beams well beyond the state-of-the-art. These novel concepts rely on an innovative reflective optic, the axiparabola, which merges the advantages of parabola mirrors and axilenses and allow to produce long and high-intensity focal lines with a tunable laser velocity.
At low laser energy, axiparabolas will be used to generate a stable, sustainable and damage-free plasma waveguide. The high-intensity beam which drives the LPA will be coupled into the so-formed waveguide in order to face diffraction and extend the distance over which electrons are accelerated.
Axiparabolas will then be used with a single high-power laser to accelerate electrons. Here we will take advantage of axiparabolas to manipulate the velocity of the laser energy-peak. This unique ability to produce superluminal and time varying velocities opens a new area of study. In the simplest case, we expect an increase of the electron energy by a factor of 8, compared to a regular parabola setup. The optimized scheme could lead to the production of 300 GeV beams with a 10 PW laser.
In both scenarios, performances will be optimized by shaping the axiparabola surface, adding a spatial phase or introducing spatio-temporal coupling. Proof of principles and exploratory experiments will be run on the Salle Jaune facility at LOA, then implemented on a PW laser facility.