Continuous-wave optical parametric oscillator based on periodically poled KTiOPO4 and its application to spectroscopy

We report a continuous-wave, doubly resonant optical parametric oscillator (OPO) based on the nonlinear material periodically poled KTiOPO4 and its ap plication to spectroscopy. The OPO, which is pumped by a diode-pumped frequ ency-doubled Nd:YLF laser at 523 nm, has a low pump-power threshold of 25 m W and can deliver 10 mW of single-frequency output at 1.65 mu m for a pump power of 200 mW. The idler wavelength can be temperature tuned at a rate of 0.73 nm/degrees C, and smooth tuning of the output frequency over similar to 3 GHz is achieved by smooth tuning of the pump laser. We demonstrate the practicality of the OPO by recording the absorption spectrum of methane ne ar 1649 nm. (C) 1999 Optical Society of America.