High Power Picosecond Laser Pulse Recirculation
We propose a novel high peak power ultrashort laser pulse re-circulation technique suitable for gamma-ray generation in Compton-backscattering sources. The two primary obstacles to higher average brightness and conversion efficiency of laser pulse energy to gamma-rays are the relatively small Compton scattering cross-section and the typically low repetition rates of Joule-class interaction lasers (10 Hz). Only a very small fraction (10{sup -10}) of the available laser photons is converted to gamma-rays, while the bulk is discarded. To significantly reduce the average power requirements of the laser and increase the overall system efficiency, we can re-circulate laser light for repeated interactions.