Mid-infrared-wavelength generation in 2-μm pumped periodically poled lithium niobate

A periodically poled lithium niobate optical parametric oscillator pumped by a Tm:YAG laser at 2.0124-mu m wavelength has been demonstrated. A pump pulse energy of 5.1 mJ generated 0.65 mJ of signal and idler pulse energy at a 50-Hz repetition frequency with a 27.8-mu m domain-period-length grating. The lithium niobate crystal at a temperature of 180 degrees C yielded 3.61- and 4.55-mu m signal and idler wavelengths, respectively. Wavelength tuning over a wide range was achieved with domain-period lengths from 25.5 to 28.2 mu m and crystal temperature tuning from 50 to 180 degrees C. Signal wavelengths of 3.26-3.76 mu m and idler wavelengths of 4.33-5.34 mu m were generated. (C) 1998 Optical Society of America.