Broadly tunable compact continuous-wave Cr2+:ZnS laser

We report the development of a continuous-wave, room-temperature Cr2+:ZnS laser that is compact and tunable over 700 nm. The laser is pumped by a diode-pumped Er-fiber laser and generates 0.7 W of linearly polarized radiation at 2.35 mum, at up to 40% slope efficiency. Cr2+:ZnS directly diode-pumped at 1.6 mum yields polarized radiation that is tunable over 400 nm at up to 25 mW of output power. A comparison of Cr2+:ZnS with Cr:ZnSe (70 mW, 350 nm) in a similar setup is given. As opposed to Cr:ZnSe, the Cr:ZnS laser is intrinsically polarized. Finally, we observe sensitization of the output radiation by a few milliwatts of the visible (470-500-nm) and near-infrared (740-770-nm) radiation. (C) 2002 Optical Society of America.