Rubidium titanyl arsenate (RTA), a crystallographic isomorph of potassium titanyl phosphate, shows promise for nonlinear-frequency generation throughout the 1–5-μm spectral region. Difference-frequency generation in an RTA crystal produced tunable output in the 3.2–4.2-μm wavelength range. A single 1.064-μm Nd:YAG laser pumped both a LiNbO3/sub> optical parametric oscillator used to generate a tunable signal beam and the RTA crystal used for difference-frequency generation. Conversion efficiencies were limited to 4% primarily by the large beam divergence of the signal beam. Phase-matching measurements were in excellent agreement with new IR-corrected RTA Sellmeier equations based on refractive-index measurements.
© 1996 Optical Society of America.
D. L. Fenimore, K. L. Schepler, D. Zelmon, S. Kück, U. B. Ramabadran, P. Von Richter, and D. Small, "Rubidium titanyl arsenate difference-frequency generation and validation of new Sellmeier coefficients," J. Opt. Soc. Am. B 13, 1935-1940 (1996)