La2SrB10O19: A Promising Ultraviolet Nonlinear Optical Crystal with an Enhanced Nonlinear Optical Effect and Shortened Cutoff Edge

The ultraviolet nonlinear optical (NLO) crystal La2SrB10O19 (LSB) has been grown through a spontaneous crystallization using a SrO–Li2O–B2O3–MoO3 flux. LSB crystallizes in the noncentrosymmetric (NCS) monoclinic space group C2 (No. 5). The crystal structure contains La/SrO10 polyhedra, Sr/LaO8 polyhedra, and double layers which are composed of B5O12 groups. In comparison with the analogue La2CaB10O19 (LCB), LSB possesses an enhanced optical second-harmonic generation (SHG) effect and a shortened cutoff edge owing to the substitution of Sr2+. Moreover, the microscopic origins of the NLO effect were theoretically analyzed and discussed by first-principles calculations.