Method of producing single-polarized lithium tantalate crystal and single-polarized lithium tantalate crystal

摘要

A method of producing a lithium-tantalate crystal comprising, at least subjecting a single-polarized lithium-tantalate crystal wherein an optical absorption coefficient at a wave number of 3480 cm⁻¹ is 0.3 cm⁻¹ or less to a heat treatment under a reducing atmosphere at a temperature of not lower than 250° C. and not higher than Curie temperature and a single-polarized lithium-tantalate crystal wherein an optical absorption coefficient at a wave number of 3480 cm⁻¹ is 0.3 cm⁻¹ or less and an electric conductivity is 1×10⁻¹² Ω⁻¹·cm⁻¹ or more. There can be provided a method of producing a single-polarized lithium-tantalate crystal in a short time efficiently wherein the surface charge generated due to a pyroelectric property can be decayed quickly by improving the electric conductivity and a single-polarized lithium-tantalate crystal.