Middle-infrared luminescence of praseodymium ions in silver halide crystals and fibers

The luminescence of AgBr, AgCl, and AgClBr crystals and fibers doped with Pr3+ ions was investigated in the middle-infrared spectral range. We measured the absorption, emission, and kinetic parameters over a broad temperature range. Strong luminescence in the spectral range 4-5.5 microm was observed for the first time to our knowledge in silver halide crystals and fibers at room temperature. No noticeable differences were observed between the crystals and the fibers. We calculated various optical parameters for Pr:AgBr and Pr:AgCl crystals, using the Judd-Ofelt approximation. Both the measured results and the calculated parameters indicate that these doped crystals and fibers would be good candidates for the fabrication of mid-IR solid-state lasers or fiber lasers.