Nonlinear optical properties of SbSI

The electrooptic (EO) effect in the paraelectric phase of SbSI crystal has been investigated in detail in the temperature range 25-80 deg C. The EO effect has been studied in constant and variable low-frequency electric fields in the range of wave-lengths 0.6-1.0 μm. The dependence of the induced birefringence on the electrical field strength has a quadratic character, and the value of the effect in variable low-frequency fields exceeds that for constant fields. The dispersion dependence of the EO effect is given. The value of the induced birefringence increases with decreasing the incident light wavelength, i.e., normal dispersion of the EO effect is observed. Some theoretical models of the EO effect are verified on the basis of the data obtained. The characteristic constants are calculated: dispersion constant, value of the fundamental absorption band shift, polarization potential and others