Optical susceptibilities of Na3La9O3(BO3)8, ternary oxyborate nonlinear single crystal: theory and experiment

Abstract

Experimental and theoretical simulations of linear and nonlinear optical susceptibilities of the novelNa3La9O3(BO3)8, a ternary oxyborate nonlinear single crystal, are reported here. The calculations werebased on one of the most accurate methods for the computation of the linear and nonlinearoptical susceptibilities of solids within density functional theory. Our calculationsshow that the edges of optical absorption for and are located at 5.2 eV, in good agreement with our measurements. The anisotropy is ingood agreement with the theoretical data. The same is true for the birefringence.We found that our calculated and measured refractive indices are in goodagreement with those obtained by previous measurements. The imaginary andreal parts of the second order second harmonic generation (SHG) susceptibilityχ222(2)(ω) andχ112(2)(ω) were evaluated. Ourcalculation shows that χ112(2)(ω) is the dominant component, which shows the largest totalReχijk(2)(0) value(2.3 pm V−1)compared to χ222(2)(ω). This value shows very good agreement with experimental data(2.0 pm V−1) obtained by previous measurements and our measurements. One specific feature of theinvestigated crystals consists in substantial anisotropy of their properties, which plays acrucial role in the observed experimental dependences.These crystals possess very highly nonlinear optical properties. Thecoefficient of the SHG is about three to five times larger than that ofKH2PO4 (KDP).