Optical Spectra Properties and Continuous-Wave Laser Performance of Tm,Y:CaF 2 Single Crystals

3 at.% Tm, x at.% Y:CaF 2 crystals ( x = 0 , 0.5, 1, 2, and 3) were grown by the vertical Bridgman method and investigated. Codoping Y 3+ ions can manipulate the local structure of Tm 3+ ions in the CaF 2 crystal and then improve the spectroscopic properties. Compared with 3 at.% Tm:CaF 2 , 3 at.% Tm, 3 at.% Y:CaF 2 crystal has several advantages. Firstly, the absorption cross section is improved from 0.35 × 10 −20 cm −2 to 0.45 × 10 −20 cm −2 at 767 nm, and the fluorescence intensity had elevated 3.4 times. Secondly, the linewidth of the fluorescence spectrum and lifetime also increased from 164 nm to 191 nm and from 6.16 ms to 8.15 ms at room temperature, respectively. Furthermore, quantum efficiency improved from 58.2% to 80.3%. The maximum laser output power of 583 mW and slope efficiency of 25.3% were achieved in 3 at.% Tm, 3 at.% Y:CaF 2 crystal under 790 nm diode pumping.