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, CHI3 * 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 χ222(2)≅16 pm/V, χ333(2)≅23 pm/V and χ311(2)≅15 pm/V, for the values of the components of the second-order susceptibility tensor. The third-rank hyperpolarizability tensor β 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 βυ = 52.1 × 10−40 m4/V and βs = 20.2 × 10−40 m4/V, respectively.