Optical homogeneity and photorefractive properties of stoichiometric and congruent lithium niobate crystals grown using charges of different origins

Abstract

A stoichiometric lithium niobate crystal (LiNbO_{3 st}) and congruent lithium niobate crystals grown from a charge prepared using cyclohexanone as an extractant (LiNbO_{3 cong}(CHN)) and a charge prepared using cyclohexanone and carboxylic acid dimethylamides as extractants (LiNbO_{3 cong}(CHN + A)) have been characterized by photoinduced light scattering and laser conoscopy. The results demonstrate that the LiNbO_{3 cong}(CHN + A) crystals are rather homogeneous along their growth direction and possess good optical properties, similar to those of the LiNbO_{3 cong}(CHN) crystal. At the same time, the LiNbO_{3 cong}(CHN + A) crystal offers significantly better electro-optical properties (r_e = 29.3 pm/V).