Mid-infrared Cr2+:ZnSe random powder lasers

We report simple methods of laser active Cr2+:ZnSe powder fabrication with average grain sizes of either similar to 10 or similar to 1 mu m without crystal growth stage. Pure, uniformly mixed ZnSe and CrSe powders annealed at 1000 degrees C for 3 days in a sealed evacuated (similar to 10(-4) Torr) quartz ampoule exhibited middle-infrared laser action at room temperature under 1.56 mu m excitation of D-2 Raman shifted radiation of Nd:YAG laser. The output-input characteristic clearly demonstrated the threshold-like behavior of the output signal with the threshold energy level of 0.5 and 3 mJ in 2.9 mm spot for 10 and 1 mu m grain sizes, respectively. (C) 2008 Optical Society of America.