Resolving the tensor components for low-symmetry, polar class 3 nonlinear optical crystals: example of BaGa2GeS6

Abstract

The magnitude and sign of the nonlinear coefficients of the trigonal BaGa2GeS6 are determined by second-harmonic and sum-frequency generation, rendering it a viable alternative to AgGaS2 for 1-μm pumped frequency down-conversion to the mid-IR.