Effect of Yb concentration on the microstructures, spectra, and laser performance of Yb: CaF2 transparent ceramics

Ytterbium‐doped calcium fluoride transparent ceramics is considered as a promising laser gain medium. How to prepare low scattering loss ceramics is the main challenge at present. In this study, a simple route of hot‐pressing method was introduced to fabricate high optical quality of Yb: CaF2 laser ceramics with different concentration of Yb ions. The influence of Yb concentration on the particle sizes of the powders, microstructure, fluorescence spectra, output power, and laser emitting spectra of Yb: CaF2 transparent ceramics was discussed. About 976 nm LD pumped CW laser operation has been demonstrated in 1, 2, 4, and 5 at.% Yb doped CaF2 ceramics. A maximum average output power of 0.809 W was obtained for the 5 at.% Yb: CaF2 ceramics with the slope efficiency was 26%.