375-W 37.5-mJ less than 170 fs laser system utilizing nonlinear pulse compression in fused silica
We present a novel, robust and efficient scheme for nonlinear pulse compression at highest average powers, which is based on self-phase modulation in a bulk nonlinear medium placed inside a multi-pass-cell (MPC). The scheme is suitable for the compression of sub-ps pulses with peak powers exceeding the threshold for catastrophic self-focusing of the nonlinear medium. Experimentally, we compress the output pulses from an Yb:YAG-Innoslab amplifier from 850 fs to <170 fs at 375 W of output power, 37.5 mJ pulse energy and almost diffraction-limited beam quality using fused silica as the nonlinear medium. The efficiency of the compression unit exceeds 90%.