High-repetition-frequency, high-energy mid-wave infrared ZnGeP₂ MOPA system

A high-repetition-frequency and high-energy ZnGeP 2 master oscillator power amplifier (ZGP-MOPA) system was demonstrated. The pump source was a 2097 nm Ho:YAG laser with maximum average power of about 140 W and repetition frequency of 2 kHz. Using this pump source, the ZGP-MOPA system obtained a mid-wave infrared laser with a maximum average power of 58.9 W and pulse width of 20.1 ns, corresponding to the pulse energy and peak power of 29.5 mJ and 1.5 MW. By adjusting the divergence of seed source to match the divergence of pump source, the beam quality factor M 2 of the ZGP-OPA was 3.9 × 3.7 (horizontal directions × vertical directions), the M 2 of the signal was 2.7, and the M 2 of the idler was 2.8. The corresponding maximum average power and pulse energy were 53.3 W and 26.7 mJ.