High-efficiency, tunable 8-9 μm BaGa₄Se₇optical parametric oscillator pumped at 21 μm

Abstract

A high-efficiency, tunable 8-9 μm optical parametric oscillator with a type-II phase-matching BaGa4Se7 crystal pumped by a 2090.7 nm acousto-optical Q-switched Ho:YAG laser was demonstrated for the first time. A maximum average idler output power of 314 mW at 8925.7 nm and 1 kHz was achieved with a pulse duration of 16 ns and a spectral bandwidth of 67.8 nm under the incident pump power of 9.58 W, corresponding to a slope efficiency of 7.44% and quantum slope efficiency of 32%. Furthermore, the idler tuning range of 8-9 μm was demonstrated. The results indicate the potential of BaGa4Se7 pumped at 2.1 μm as a candidate for realizing high-efficiency long-wavelength infrared laser radiation.