12 µm Raman lasers in NH3pumped by low-power CO2laser pulses

We report the operation of optically pumped 12 μm lasers in NH3using peak pumping powers as low as 2 W. These low pumping powers represent a 1-2 order-of-magnitude improvement over previously published threshold values. Measurements of the lasing offset frequency clearly demonstrate that a two-photon Raman process is responsible for optical gain at 12 μm. In light of our results, we discuss the feasibility of an optically pumped CW 12 μm laser.