Increased Optical Damage Resistance and Transparency in MgO-Doped LiTaO₃ Single Crystals

Clear and transparent 2-inch diameter undoped and MgO-doped LiTaO 3 single crystals with few Fe impurities have been grown by the conventional Czochralski method from a congruent melt. The optical damage resistance of undoped LiTaO 3 has been characterized by the measurement of photoinduced birefringence change and is lower than that of commercially available LiNbO 3 , which is not consistent with the previously reported data in the literature. In addition, doping of a few mol% MgO further improved the optical damage resistance, transmission in the visible light region, and crystal decolorization, and produced a favorable shift of absorption edge toward shorter wavelengths for lithium tantalate. These are important advantages when considering shorter- wavelength accessibility and high conversion efficiency in second-harmonic- generation devices.