Spectroscopic and laser properties of the Ho3+ ions optical centers in CaF2 and SrF2 crystals

Different Ho3+ ion optical centers in CaF 2 and SrF 2 crystals were separated and their spectroscopic properties at the 5I 8 ↔5I 7 laser 2.1 μm transition were investigated at 14K. For the first time room temperature lasing is obtained in Ho:SrF 2 crystal under resonant (1948nm) pumping.