Pump wavelength tuning of a near-infrared optical parametric oscillator

Optical parametric conversion in a potassium titanyl phosphate crystal with a tunable alexandrite laser was investigated as a function of pump wavelengths in the 700-800-nm region. Threshold energies and slope efficiencies for a doubly resonant oscillator configuration were measured for pump wavelengths of 744, 766, and 780 nm. Phase-matching conditions and a theoretical analysis using Sellmeier's equations provide good agreement with experimentally measured values of signal and idler wavelengths as a function of the pump wavelengths.