CPA Laser System Based on Yb Fiber Seeder and two Cascade Yb:YAG Amplifier for Compact OPCPA Pump Source

Summary form only given. Compact laser generating high energy (multi-mJ), high repetition rate (1 kHz), short duration (<; 1 ps) pulses would be a promising pump source for optical parametrical chirped pulse amplification (OPCPA) system [1]. Ytterbium (Yb) doped laser crystals (e.g. Yb:YAG) possess some highly desirable properties, like low quantum defect, broad amplification bandwidth, low excited state absorption, for efficient generation of sub-ps pulses in specified range. However, direct amplification of such pulses to high peak power is limited by various nonlinear effects (Kerr lensing, self-focusing, self-phase modulation, Raman scattering, etc.). Chirped pulse amplification (CPA) is a common method to significantly reduce these effects. In a CPA scheme, pulses are stretched, amplified and then re-compressed to achieve high peak power transform-limited pulses at the output and to significantly reduce peak power in the amplification medium. In this work an all-in-fiber seed source and two cascade free-space amplifier based on Yb:YAG crystal for energy scaling has been developed and demonstrated. Pulses were compressed in a 4-pass diffraction grating compressor. The principle scheme, which was based on our previous setup, is presented in Fig. 1 [3]