Narrow-linewidth BaGa4Se7 optical parametric oscillator
Jintian Bian, Hui Kong, Qing Ye, Jiyong Yao, Lei Guo, Xiaoquan Sun
Abstract
The linewidth of the BaGa 4 Se 7 (BGSe) optical parametric oscillator (OPO) was narrowed for the first time, to the best of our knowledge, by inserting a Fabry-Perot (FP) etalon into an L-shaped cavity. When a 15 mm long BGSe (56.3, 0) was pumped by a 1064 nm laser, the peak wavelength was 3529 nm, and the linewidth was 4.53 nm (3.64 cm -1 ) under type I phase matching. After inserting a 350 m thick FP etalon, the linewidth was decreased to 1.27-2.05 nm. When the tilt angle of the etalon was 2.34, the linewidth was 2.05 nm (1.65 cm -1 ), and the peak wavelength was still 3529 nm. When the tilt angle of the etalon was 3.90, the peak wavelength was 3534.9 nm, and the linewidth was 1.27 nm (1.02 cm -1 ), which was the narrowest linewidth of a BGSe OPO, to the best of our knowledge. The beam quality was also improved after inserting the FP etalon.