Zinc germanium phosphide optical parametric oscillator

This paper reported a ZGP (zinc germanium phosphide) optical parametric oscillator (OPO) pumped by high-repetition rate 2 mm OPO. Type Ⅰ ZGP crystal (ZnGeP2) with the size of 5.5 mm×6 mm×18 mm was cut at phase matching angles of 55° and 0°. Under 4.0 kHz repetition rate, 310 mW mid-IR laser was obtained when the random polarization 2 mm pumping power was 5.2 W. The optical-to-optical efficiency of the p-polarized 2 mm to 3~5 mm was 12%. The experimental wavelength tuning curve of ZGP OPO was also achieved by tuning the angle of the ZGP crystal. It accorded with the theoretical rule in the error range.