High-Resolution Laser in Widely Tunable Range (4.16-7.13 m) Based on Mid-Infrared BaGa₄Se₇ Optical Parametric Oscillator Pumped at 1064 nm

A widely tunable 4.16-7.31 mu m high-resolution mid-infrared optical parametric oscillator with a type-I BaGa4Se7 (BGSe) crystal pumped by a 1064 nm laser was demonstrated for the first time. We have achieved a wavelength tuning accuracy of less than 5 nm through simultaneously performing temperature tuning and angular tuning on the BGSe (46 degrees, 0 degrees) Optical Parametric Oscillation (OPO). The wavelength resolution will be less than 1 nm when using commercial temperature control equipment.