We report on the rotation of the indicatrix in the mirror plane and the refractive indices of Sn2P2S6 single crystals in the wavelength range 550−2200 nm at room temperature. Electro-optical properties of Sn2P2S6 were also measured by direct interferometric technique for electric fields applied parallel to the crystallographic x-axis that lies near the spontaneous polarization vector. The room temperature free electro-optical coefficient reaches 174 ± 10 pm/V at λ = 633 nm and shows only weak dispersion in the wavelength range between λ ≈ 0.6 … 1.3 μm. The temperature dependence of the electro-optical coefficients near the structural phase transition at TC = 65◦C is well described by a Curie-Weiss law with a peak value .
© 2005 Optical Society of AmericaPDF Article