Preparation and Spectral Properties of Er, Na:CaF2 Transparent Ceramics.

Er3 +, Na+ co-doped CaF2 transparent ceramics with Er3 + dopant concentration of 3% and Na+ of 0%, 0. 5%, 1.0%, 1.5% and 2.0% were fabricated by the vacuum hot pressing method with 16 mm in diameter and 3 mm in thickness. The average grain size of the obtained Er, Na∶CaF2 powders varied from 28 nm to 36 nm with the shape of sphere. The effects of Na+ doping on the transmittance, microstructure and spectral properties of Er3 + ∶CaF2 transparent ceramics were investigated. The transmittance of all the obtained ceramic samples is above 84% in the wavelength of 1 000 nm. The results show that after introducing Na+ into Er3 + ∶CaF2 transparent ceramics, charge-neutralized Er3 + -Na+ structure formed which prevent Er3 + from clustering. The emission spectra of Er3 + in CaF2 transparent ceramics at around 1. 5 and 2. 7 μm could be modulated by adjusting the concentration of Na+ and the near-infrared fluorescence lifetime at around 1. 5 μm increase with the increasing of Na+ concentration, reaching a maximum of 56.75 ms. [ABSTRACT FROM AUTHOR]