Fe2+-doped CdSe single crystal: growth, spectroscopic and laser properties, potential use as a 6 μm broadband amplifier

We report on the successful growth of single crystals of Fe2+:CdSe by seeded physical vapor transport (SPVT) technique with doping within the growing process and subsequent annealing in Se vapor. Luminescence lifetime measurements, spectroscopic studies of E-5-T-5(2) transition of Fe2+ in CdSe, and laser experiments were performed. The lifetime of the T-5(2) energy level was measured to be 20 +/- 5 ns at a room temperature (RT) of 290 K. At liquid nitrogen (LN) temperature, luminescence kinetics displayed a non-exponential decay, which can be fitted to a bi-exponential function with time constants tau(1) = 6 mu s and tau(2) = 29 mu s. As much as 3.2 mJ of output energy at 5.2 mu m with 27% absorbed pump energy slope efficiency of an Fe2+:CdSe laser was achieved at RT under 2.94 mu m nanosecond Er:YAG laser pumping. The Fe2+:CdSe laser was tuned from 4.63 to 6.10 mu m. Obtained characteristics of Fe2+: CdSe indicate that the crystal can be considered a promising medium for amplification of femtosecond pulses in the middle infrared range up to 6 mu m.