Research progress of new chalcogenides in mid-infrared nonlinear optical crystals

The frequency conversion of existed laser sources using infrared nonlinear optical (NLO) crystals is the main way to generate 3-5 m and 8-12 m atmospheric windows infrared sources. The traditional infrared nonlinear optical crystals have shortcomings of one kind or another which seriously limits their applications and cannot meet the application requirements. Therefore, it is practically and scientifically important to study and search for new infrared NLO crystals. In this paper, an overview on the progress of searching for new infrared NLO crystals in chalcogenides was presented. The new development in the growth and characterization of LiMQ2(M=Ga, In;Q=S, Se, Te),BaGa4S7,BaGa4Se7,BaGa2MQ6(M = Si, Ge;Q = S, Se), and Li2In2MQ6 (M = Si, Ge;Q = S, Se) was reported.