Turn-key, liquid-nitrogen-cooled 3.9 µm semiconductorlaser package with 0.2 W CW output

Abstract
A CW 3.9 µm diode-pumped InAsSb/GaSb laser yielded 0.2 W at 84 K and 0.26 W at ~68 K in a collimated beam, limited only by the pump power. The beam exhibited 62% coupling efficiency into a 250 µm core, 0.2 NA infrared fibre.