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We present two beam coupling characterization of Ba 0.77 Ca 0.23 TiO 3 , 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 Ba 0.77 Ca 0.23 TiO 3. 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).

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Nominally pure and rhodium-doped barium-calcium-titanate crystals of the congruently melting composition Ba 0.77 Ca 0.23 TiO 3 (BCT) are grown by the Czochralski technique. These crystals are characterized by holographic and conventional electrical experiments. The doped samples have an absorption maximum at 630 nm. They are hole conductive, and for intensities between 0.1 and 1 W cm −2 all properties are explained within a one-center charge-transport model. Two-beam-coupling gain factors up to 8 cm −1 are obtained, and doping with rhodium increases the effective trap density. Although diffusion is the dominant charge-driving force, bulk photovoltaic currents also occur which are especially pronounced in the range between 460 and 640 nm.