Czochralski growth of α-BBO crystals under azimuthally anisotropic heating

Abstract

Crystal growth of α-BBO in a modified low-gradient Czochralski furnace was performed. The distribution of temperature inside the furnace was described by a three-fold symmetry axis (L 3). The axial temperature gradient under the melt was ∼2 K/cm, while that inside the melt was almost equal to zero. A 36 mm thick sample of the grown crystal shows extremely low 0.05 cm −1 absorption coefficient at wavelengths >220 nm.