A theoretical model of the linear electro-optic effect

A simple theoretical study of the linear electro-optic effect is presented. This semiclassical approach is based on the single-energy-gap model, the dielectric theory and the concepts of bond charge and effective ionic charge. A general expression is obtained for the electro-optic coefficient of a crystal and is applied to a wide variety of diatomic and ternary compounds including zincblende (GaAs, GaP, ZnSe, ZnS, ZnTe, CuCl), wurtzite (ZnS, CdS, CdSe), quartz (SiO2), lithium niobate (LiNbO3, LiTaO3), KDP (KH2PO4, KD2PO4, NH4H2PO4), chalcopyrite (AgGaS2, CuGaS2) and proustite (Ag3AsS3). The calculated results are generally in good agreement with experiment.