Mid-infrared spectral properties and laser performance of Er3+ doped CaxSr1-xF2 single crystals

Er3+ doped CaxSr1-xF2 (x = 0, 0.5, 0.7, 1) single crystals were successfully grown by the temperature gradient technique (TGT) and their compositional dependence of various spectral properties has been systematically studied. The spectroscopic investigation showed that with the variation of x, there was a significant difference for the spectral parameters including stimulated emission cross section around 2.8 μm and the related fluorescent lifetimes. The lifetime gap between Er3+: 4I13/2 and Er3+: 4I13/2 was effectively narrowed for x = 0.5, which contributed to the high efficient mid-infrared (MIR) laser.