High-power Yb:KYW picosecond regenerative amplifier for optical parametric amplifier pumping

A 10 Hz, 10 mJ-level Yb:KYW diode-pumped regenerative amplifier for picosecond pulses at 1040 nm was developed. It will be used in front end of the PHELIX petawatt laser system at the Helmholtz-Center GSI to pump an optical parametric amplifier (OPA) for temporal contrast enhancement. In order to achieve a high temporal contrast, this regenerative amplifier is used as the pump source in a chirped-pulse amplification arrangement, which generates picosecond pulses before frequency doubling. For synchronization purposes, the seed pulses are derived from the femtosecond oscillator of the petawatt laser system, frequency shifted and pre-amplified by two fiber amplifiers.