Optical properties of lithium-rich lithium niobate fabricated by vapor transport equilibration

Lithium-rich lithium niobate of excellent optical homogeneity can be fabricated by a vapor transport equilibration (VTE) technique. The high-optical-quality, uniformly birefringent crystals noncritically phase match for second-harmonic generation of 532-nm radiation from 1064-nm Nd:YAG radiation at 238°C. The refractive indexes and their temperature dependence have been measured and used to derive temperature-dependent Sellmeier equations, which predict noncritical phase matching for wavelengths as short as 976 nm to generate blue at 488 nm at room temperature. The Sellmeier equations accurately predict experimental phase-matching temperatures over a wide temperature range