INCREASED OPTICAL-DAMAGE RESISTANCE AND TRANSPARENCY IN MGO-DOPED LITAO3 SINGLE-CRYSTALS

Clear and transparent 2-inch diameter undoped and MgO-doped LiTaO3 single crystals with few Fe impurities have been grown by the conventional Czochralski method from a congruent melt. The optical damage resistance of undoped LiTaO3 has been characterized by the measurement of photoinduced birefringence change and is lower than that of commercially available LiNbO3, 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.