It has been known for over two decades that the birefringence of stoichiometric LiNbO3 is higher than that of congruent LiNbO3. This allows phase matching at higher temperatures or for shorter wavelengths. The usefulness or stoichiometric LiNbO3 is limited by inhomogeneous growth due to incongruent melting. The vapor phase equilibration technique1 allows any composition, including stoichiometric, to be fabricated with excellent homogeneity. We report here measurements of the optical properties of crystals at the lithium-rich phase boundary. The crystals noncritically phase match for SHG of 1.064-µm radiation at 238°C and for wavelengths as short as 488 nm at room temperature.
© 1989 Optical Society of AmericaPDF Article