A high-energy, long-wave infrared laser based on ZnGeP2 optical parametric oscillator and amplifier

This paper reports on a high-energy, long-wave infrared source that is pumped using two individual Ho: YLF lasers, which presents an effective approach to improving the energy and peak power of the long-wave laser. A 7.23-mJ nanosecond pulse at 8.027 mu m was achieved using a ZnGeP2 optical parametric oscillator and amplifier (OPO + OPA) system. The optical conversion efficiency of the system was 7.8 %, achieved with a total pump energy of 92.15 mJ. The ZnGeP2 OPO provided an output energy of 2.68 mJ, accompanied by a pulse duration of 12.4 ns. Furthermore, the pulse energy was boosted to 7.23 mJ after optical parametric amplification, resulting in a peak power increase to 0.58 MW. The amplified long-wave laser has a linewidth of 86.26 nm, and M-2 factors of 3.44 in the x direction and 2.94 in the y direction.