Electro-optic, dielectric, and elasto-optic properties of photorefractive BaTiO3 crystal

Measurements on high quality samples of top-seeded-solution-grown crystal BaTiO3 have been performed in order to complete the set of data, which is necessary to describe the optic response of this material to electric fields and elastic deformation.1 Improvements in the accuracy of some previously published results could be obtained because of better optical quality and larger size of the crystal samples that are available nowadays. The most important results are the values and the signs of the piezoelectric coefficients d311 and d333, the absolute values of the elasto-optic coefficients, and all the electro-optic measurements. Both low frequency electro-optic measurements in a stress-free sample and the measurements in the inertia-clamped samples using a step-like electric field were used to correct the previous results. The complete set of material parameters of the BaTiO3 crystals at room temperature has been afterwards determined by a numerical fitting procedure. The signs of the elasto-optic coefficients could also be determined with great confidence. We propose that the new calculated values are used as a consistent set of material parameters of the BaTiO3 crystal, in particular for describing its photorefractive properties, that is, to calculate its effective electro-optic and dielectric properties.