Electro-optic properties in pure LiNbO3 crystals from the congruent to the stoichiometric composition

Abstract

We report large and nonmonotonic dependences of the electro-optic (EO) coefficient r22 and the corresponding dielectric permittivity in pure LiNbO3 on the concentration of intrinsic defects related to the deviation from the stoichiometry of the crystal. This variation is caused mainly by the electro-mechanical contribution. A stoichiometric crystal possesses both large EO properties and resistance to optical damage which renders it much more suitable for use in laser Q-switching than the congruent crystal.