Acentric nonlinear optical 2,4-dihydroxyl hydrazone isomorphic crystals with large linear, nonlinear optical susceptibilities and hyperpolarizability

Abstract

A systematic ab initio study of the linear, nonlinear optical susceptibilities, and hyperpolarizability of noncentrosymmetric-monoclinic 2,4-dihydroxyl hydrazone isomorphic crystals (DHNPH) within density functional theory in the local density approximation (LDA), general gradient approximation (GGA), the Engel-Vosko generalized gradient approximation (EV-GGA) and modified Becke-Johnson potential (mBJ) has been performed. The complex dielectric susceptibility dispersion, its zero-frequency limit and the birefringence are studied. Using scissors' corrected mBJ we find a large uniaxial dielectric anisotropy (∼0.56) resulting in a significant birefringence (0.61). We also find that 2,4- DHNPH possess large second harmonic generation. The calculated second order susceptibility tensor components for the static limit |χ111 (2)(0)| and |χ111 (2)(ω)| at λ=1.9 μm (0.651 eV) and at λ = 1.064 μm (1.165 eV) are 53, 91, and 209 pm/V, respectively. A remarkable finding, applying the scissors' correction has a profound effect on value, magnitude and sign of χijk (2)(ω). In additional we have calculated the microscopic hyperpolarizability, β 111, vector component along the principal dipole moment directions for the dominant component. We find that the value of β 111 equal to 47 - 10 -30 esu, in good agreement with the measured value (48.2 - 10 -30 esu).