Effect of sintering temperature on the microstructure and optical properties of Mn: CaF2 transparent ceramics

5 at.% Mn: CaF2 nanoparticles were used to fabricate transparent Mn: CaF2 ceramics by hot pressing method at the sintering temperature varying from 700 °C to 1000 °C. The microstructure and optical transmittance of the samples were characterized by FE-SEM and UV-Vis-IR spectrophotometer. It was found that the average grain size of Mn: CaF2 ceramics increased with the increase of sintering temperature, whereas the relative density firstly increased and then decreased. The highest density of Mn: CaF2 ceramic reached 99.13% at 900 °C, and its average grain size was about 1.95 μm. The best in-line transmittance was at 900 °C, with transmittance being about 51.49% at 640 nm and 90.2% at 2000 nm, respectively. The excitation and emission spectra of Mn: CaF2 ceramic were also measured and discussed.