Cryogenic 750-mJ Ti:sapphire amplifier for laser plasma acceleration at a 100-Hz repetition rate

Laser plasma acceleration (LPA) is rapidly evolving from proof-of-principle experiments to stable and reliable accelerator operation. An important next step in this evolution is to increase the repetition rate to enable performance improvements through active stabilization of electron parameters using fast feedback loops. Today, laser-plasma accelerators are typically driven by Ti:sapphire lasers, but their high quantum defect and pump laser requirements limit the repetition rate and average power. Here, we present a Ti:sapphire laser system that pushes these limits and delivers 750 mJ laser pulses at a repetition rate of 100 Hz and a spectrum that supports sub-30 fs duration. High beam quality is achieved by careful thermal management and control of thermal lensing in the cryogenically cooled amplifier crystal.