Spectroscopy and tunable mid-infrared lasing of a novel gain medium: Cr2+-doped Cd0.85Mn0.15Te

A novel mid-infrared transition-metal laser has been developed based on chromium (II)-doped Cd0.85Mn0.15Te. The characteristic spectroscopic features of Cr2+: Cd0.85Mn0.15Te are large absorption and emission cross sections (similar to 10(-18) cm(2)), a predicted absence of excited state absorption (ESA), and a broad emission band extending from 2.1 similar to 3.5 mu m. The broad emission band makes Cr2+: Cd0.85Mn0.15Te very attractive for the development of a widely tunable mid-infrared laser. In initial studies, a laser tunability from 2.3 to 2.75 mu m has been demonstrated with a full width at half maximum of 2.3 nm. A larger tuning range seems possible with the appropriate optics. The highest slope efficiency achieved for a pulsed (2 Hz) free-running laser was 44.2 %.