Tunable 10- to 11-μm CdSe optical parametric oscillator pumped by a 2.1-μm Ho:YAG laser

We demonstrated a CdSe optical parametric oscillator (OPO) pumped by a 2090.7-nm Ho:YAG laser at a pulse repetition frequency of 500 Hz. Up to 140 mW output which corresponds to a pulse energy of 280 μJ was obtained at the idler wavelength of 10.28 μm with a pump power of 7 W. The idler pulse width was 19 ns when pumped by a 32 ns pulse. The idler wavelength can be tuned from 10.07 to 11.1 μm. With 6.3 W pump, the output power at 11.1 μm reached 46 mW (92 μJ pulse energy). To the best of our knowledge, 11.1 μm was the longest wavelength obtained with a 2.1-μm laser pumped CdSe OPO.