High-pulse-energy mid-infrared optical parametric oscillator based on BaGaSe crystal pumped at 1.064 μm.

We have demonstrated a high-pulse-energy nanosecond mid-infrared optical parametric oscillator (OPO) based on the nonlinear crystal BaGaSe pumped by 1.064 µm Nd:YAG laser. The experimental OPO threshold of 7.97 MW/cm was in good agreement with the theoretical calculation of 8.05 MW/cm. The maximum pulse energy of the idler wavelength was 2.56 mJ at 4.11 µm wavelength when the pump energy was 61.6 mJ, corresponding to an optical-to-optical conversion efficiency of 4.16%. The idler wavelength can be continuously tuned in the range from 3.12 to 5.16 µm. [ABSTRACT FROM AUTHOR]