Red and blue light generation by frequency doubling and tripling in periodically poled LiNbO/sub 3/

Summary form only given. Periodically poled LiNbO/sub 3/ (PPLN), with its high optical nonlinearity and noncritical phase matching, is an attractive nonlinear material for generating high-power visible output via frequency upconversion of existing infrared sources. In this work, we demonstrate second- and third-harmonic generation of an Nd:YAG laser (1320 nm) to produce red (660 nm) and blue (440 nm) wavelengths with high spatial beam quality in a simple single-pass arrangement. Samples of PPLN were prepared with the electric-field poling technique. The results demonstrate the capability of sum-frequency generation, even in a third-order interaction, to generate significant powers of blue (440 nm) light in PPLN. Additionally, results show that photorefractive effects can be successfully eliminated in undoped LiNbO/sub 3/ at this short wavelength. Provision of antireflection coatings for optics and crystals and optimization of beam overlap in the frequency-mixing process should all offer a significant improvement in performance.