Continuous-wave fiber-pumped Cr2+: ZnSe laser

Abstract

Power performance of a compact, broadly tunable, continuous-wave (cw) Cr2+:ZnSe laser pumped by a thulium fiber laser at 1800 nm was investigated. In the lasing experiments, a Cr2+:ZnSe sample with a small-signal differential absorption coefficient of 11 cm(-1) and a fluorescence lifetime of 4.6 mu s was used. An astigmatically compensated x-cavity with 15% output coupler produced as high as 640 mW of output power at 2480 nm with 2.5 W of incident pump power. Resonator losses were investigated using three different methods, and an in-depth analysis of the results was performed. The stimulated emission cross section values determined from laser threshold data and fluorescence measurements were in good agreement with each other. Finally, broad, continuous tuning of the laser was demonstrated between 2240 and 2900 nm by using an intracavity Brewster-cut MgF2 prism and a single set of optics.