Photorefractive two beam coupling characterization of a Barium-Calcium titanate crystal

Abstract : We present two beam coupling characterization of Ba0.77Ca0.23TiO3, a ferroelectric material with no phase transition around room temperature that shows high photorefractive gain (7cm-1 with ordinary polarization and 15cm-1 with extraordinary polarization). We measure the electrooptic coefficients of Ba0.77Ca0.23TiO3. These values are compared to estimated theoretical values, calculated using a model that allows to deduce the tetragonal phase parameter (Pockels and piezoelectrics coefficients) from the parameters of the high temperature cubic phase (Kerr and electrostriction coefficients)