Today there is a wide interest in middle Infrared lasers for applications such as remote sensing and IR spectroscopy. Although a significant effort has been made worldwide to develop such lasers, the results obtained so far have been limited, because of a lack of host materials with the desired properties such as optical transparency and low phonon energy. Silver halide single crystals AgCl_xBr_1-x (0<x<1) doped with transition metals ions are good candidates as the active materials for lasing in mid IR spectral range.

In this work we studied the optical properties of silver halide crystals doped with transition metals ions: Ni²⁺, Co²⁺. The emission, excitation, and absorption spectra, as well as the kinetic parameters, were measured for various temperatures. Strong emission band was observed between 2-3.5mm. The band width and the band position of the emission band in the mid-IR as a function of temperature was measured and good agreement with the theoretic prediction was found.

The mean crystal field strength (10Dq) and Racah parameter (B) of the Ni⁺² doped AgBr and AgCl crystals were calculated.

We have shown that Ni doped silver halide crystals may serve as tunable laser media, at low temperatures, in the mid IR.