Optical properties of SrF(2) and SrF(2):Ce(3+) crystals codoped with In(3+)

The paper presents the results of a comprehensive study of effects that In(3+) ion impurities have on the optical properties of SrF(2) and SrF(2):Ce(3+) crystals. The investigations were carried out both by optical spectroscopy methods and ab initio quantum chemical calculations. To estimate the effect of indium impurities on the optical band gap of the crystals, the DFT calculations were performed for SrF(2) crystals doped with different concentrations of In(3+) ions. The study of SrF(2) crystals co-doped with Ce and In ions reveals the highly effective role of indium ions in reducing the electron trapping efficiency in the processes of excitation transfer to an activator. This improvement is associated with some change in the band gap of the crystals caused by indium doping, which is confirmed by both theoretical and experimental results.