Evaluation of electro-optic, elasto-optic, piezoelectric, and elastic coefficients of Ba0.77Ca0.23TiO3 through orientation dependent photorefractive beam coupling

Abstract : We present a demonstration of the influence of the indirect electro-optic effect on the photorefractive performance of Ba0.77Ca0.23TiO3 ~BCT!. The comparison of the orientation dependence of the two-beam coupling energy transfer gain with theoretical model allows us to obtain information on the electro-optic coefficients, but also an evaluation of the unknown elasto-optic, piezoelectric, and elastic stiffness coefficients of BCT. We found r13 T 533 pmV21 and r33 T 5170 pmV21. These values are in good agreement with other published values. For the interesting coefficient r42 T , we find a higher value r42 T 5465 pmV21 than the one previously published. From this study we also determine that as in the case of BaTiO3 , the optimal orientation is given by a 45°-cut BCT