∼2.9 μm continuous-wavelength laser operation of fiber-pumped Ho,Pr:CaF2 single crystals

Ho,Pr:CaF2 single crystals were grown by modified temperature gradient technique method (TGT). A systematic study on the fluorescence characteristics around 2.9 μm has been carried out on this kind of materials for the first time, to the best of our knowledge. After co-doping with Pr3+, the population inversion is much easier to realize and the ratio of populations between the upper and lower energy levels is highest among the reported materials, which shows the Ho,Pr co-doped CaF2 is a kind of promising materials. The continuous-wavelength (CW) laser operation has been achieved with the maximum output power of 154 mW on 1%Ho,0.1%Pr:CaF2 crystals. It's the first report about the CW laser output on Ho-doped CaF2 single crystals.