High-power laser pulse recirculation for inverse Compton scattering-produced -rays

Inverse Compton scattering (ICS) of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic γ -ray production. The efficiency of γ -ray generation via ICS is severely constrained by the small Thomson scattering cross-section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated γ -rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. ICS of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average γ -ray brightness in the next generation of sources.