GROWTH AND CHARACTERIZATION OF OFF-CONGRUENT LINBO3 SINGLE-CRYSTALS GROWN BY THE DOUBLE CRUCIBLE METHOD

Off-congruent LiNbO3 Single crystals were grown from melts with Li-rich compositions (58.0 mol% Li2O) by using the double crucible method. The composition of crystals grown from melts with 58 mol% Li2O was found to be 49.8 mol%, close to the stoichiometric composition. The compositional variation throughout the crystal grown by the double crucible method was measured to be within 0.094 mol% by the results of SHG phase-matching temperature measurements. X-ray topography, X-ray rocking curves and extinction ratios indicate that the crystal quality of the off-congruent crystal is lower than that of the congruent crystal. The Li-rich crystals exhibit a strong photorefractive effect as compared with the congruent crystals. The Li-rich crystals grown from melts with 58.0 mol% Li2O were found to be single domain in the as-grown state.