Growth, spectroscopic properties and up-conversion of Yb, Pr co-doped CaF2 crystals

Abstract

Yb,Pr:CaF2 crystals have been grown successfully by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, fluorescence decay lifetime of Pr3+ ions in CaF2 crystal sensitized by different Yb3+ ions concentration have been measured. The effective J-O intensity parameters were fitted to be Ω2=0.36 × 10−20cm2, Ω4=2.89 × 10−20cm2, Ω6=6.69 × 10−20cm2 for 0.3 at.%Pr,1.5 at.%Yb:CaF2. And the emission cross sections of 3P1→3H5 (535 nm), and 3P0→3F4 (750 nm) are calculated to be 2.02 × 10−20cm2, and 2.50 × 10−20cm2 with the FWHM of 17.2 nm, and 10.5 nm, respectively. The fluorescence lifetime of 3P0 has achieved great increasing by sensitizing of Yb3+ ion. Not only the up-conversion luminescence can be achieved, but also the broad band emission from 1D2 energy level can be observed. The results show that Yb,Pr:CaF2 could be a potential laser gain medium for visible and near-IR laser operation.