RUBIDIUM TITANYL ARSENATE DIFFERENCE-FREQUENCY-GENERATION AND VALIDATION OF NEW SELLMEIER COEFFICIENTS

Rubidium titanyl arsenate (RTA), a crystallographic isomorph of potass ium titanyl phosphate, shows promise for nonlinear-frequency generatio n throughout the 1-5-mu m spectral region. Difference-frequency genera tion in an RTA crystal produced tunable output in the 3.2-4.2-mu m wav elength range. A single 1.064-mu m Nd:YAG laser pumped both a LiNbO3 o ptical parametric oscillator used to generate a tunable signal beam an d the RTA crystal used for difference-frequency generation. Conversion efficiencies were limited to 4% primarily by the large beam divergenc e of the signal beam. Phase-matching measurements were in excellent ag reement with new IR-corrected RTA Sellmeier equations based on refract ive-index measurements. (C) 1996 Optical Society of America.