High-Power Picosecond Pulse Recirculation for Inverse Compton Scattering

In the next generation of linear colliders, inverse Compton scattering (ICS) of intense laser pulses on relativistic electron bunches will enable a mode of operation based on energetic γe and γγ collisions, with a significant complementary scientific potential. The efficiency of γ-ray generation via ICS is constrained by the Thomson scattering cross section, resulting in typical laser photon-to-γ efficiencies of <10−9. Furthermore, repetition rates of the state-of-art high-energy short-pulse lasers are poorly matched with those available from electron accelerators. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. We propose and experimentally demonstrate an alternative, non-interferometric method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J [ I. Jovanovic, M. Shverdin, D. Gibson, and C. Brown, Nucl. Instrum. Methods A 578 160 (2007)]. ICS of recirculated Joule-level laser pulses is compatible with the proposed pulse structure for ILC and has a potential to produce unprecedented peak and average γ-ray brightness in the next generation of sources.