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 (7 cm(-1) with ordinary polarization and 15 cm(-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 one to deduce the tetragonal phase parameter (Pockels and piezoelectric coefficients) from the parameters of the high-temperature cubic phase (Kerr and electrostriction coefficients).