Potassium niobate optical parametric oscillator pumped by the second harmonic of a garnet laser

An experimental investigation was made of a KNbO₃ crystal as a nonlinear element of an optical parametric oscillator (OPO). A tuning range of 0.86–1.4 μ and a conversion efficiency higher than 5% were achieved. Experimental investigations were made of the 2ω phase-matching angles and temperatures for various pump wavelengths, of the optical quality of the crystals and their optical damage threshold, and of the parameters of growth and conversion of potassium niobate crystals to the single-domain state. The output characteristics of a potassium niobate OPO were compared with those of lithium and barium sodium niobate OPO's.