The optimal phase-matching angles for third harmonic generation of low symmetry nonlinear optical crystal La2CaB10O19

Abstract The signs of nonlinear optical (NLO) coefficients of La 2 CaB 10 O 19 (LCB) crystal were determined by Maker fringe method and phase-matching method. Compared with d 22 , the signs of d 21 and d 23 are found by Maker fringe method to be negative and positive, respectively, and the sign of d 14 is found to be positive by phase-matching method. Phase-matching angles for third harmonic generation (THG) in LCB crystal were calculated and verified by experiments. The distribution of effective NLO coefficient ( d eff ) and the optimal phase-matching angles for THG with LCB crystal are determined for the first time, with optimal phase-matching angles of (48.7°, 72.5°) and (65.3°, 37.5°) for type-I and type-II THG, respectively. The results show that LCB is an excellent NLO crystal for THG application.