Optical and luminescence properties of Co:AgCl_0.2Br _0.8 crystals and their potential applications as gain media for middle-infrared lasers

Infrared absorption and luminescence emission of cobalt doped silver halide crystals were investigated at room temperature and at low temperatures. A broad absorption band was observed in the near-infrared (1.4-2.5 m) and a broad emission band in the middle-infrared (3.5-5.2 m). The emission lifetime varied between 1.73 ms at low temperatures and 5 s at room temperature. Based on the measured parameters and theoretical calculations, we believe that there is an excellent chance that these crystals would lase in the mid-IR. Moreover, it would be possible to extrude fibers from the crystals and obtain mid-IR fiber lasers.