Low-Threshold Mid-Infrared Optical Parametric Oscillator UsingPeriodically Poled LiNbO₃

We report the generation of tunable mid-infrared optical pulses using all-solid-state pumped optical parametric oscillator in a periodically poled lithium niobate. Several ways were used to lower the threshold, resulting in a mean threshold as low as 6.5 mW and an achievement of wavelength conversion in the 2.77-4.04 μm spectral range. Continuous tuning range from 2.97 to 3.25 μm was achieved. The maximum idler output power of 466 mW at the wavelength of 3.41 μm was obtained, which represents an optical-to-optical conversion efficiency of 19% from incident pump power to the idler output.