Second-harmonic generation in the crystalline complex antimony triiodide-sulfur

Crystals of the 1: 3 complex between antimony triiodide and sulfur, SbI3 * 3S₈, are found to possess a high second-order optical nonlinearity. The powder second-harmonic generation efficiency is found to be approximately half of that of the isostructural complex of iodoform with sulfur, CHI_3* 3S₈. Second-harmonic generation can be phase matched. The phase-matching angle of type I is found to be approximately 30° at the fundamental wavelength 1.064 μm. The Maker fringes’ measurements give x⁽²⁾₂₂₂ ≊ 16 pm/V, x⁽³⁾₃₃₃ ≊ 23 pm/V, and X³₃₁₁ ≊ 15 pm/V for the values of the components of the second-order susceptibility tensor. The third-rank hyperpolarizability tensor j was decomposed into irreducible parts; the norms of the vector part and the septor (octupolar) part in the SbI₃ * 3S₈ complex were evaluated to be β_v = 52.1 × 10^-40 m⁴/V and β₈ = 20.2 × 10^-40 m⁴/V, respectively.