Effect of NaF doping on the transparency, microstructure and spectral properties of Yb3+: CaF2 transparent ceramics

Abstract Yb3+:CaF2 transparent ceramics are promising laser gain media with outstanding performance. However, low transmittance in the visible range is the main challenge that restricts the application of Yb3+:CaF2 ceramics in the laser system. In this paper, a new scheme to eliminate the residual pores in the Yb3+:CaF2 transparent ceramics based on doping of NaF as a sintering aid is proposed. Microstructural characterization indicated that NaF could inhibit the grain growth and increase the transmittance in the visible range significantly. The corresponding transmittance was measured to be 85% at the wavelength of 400 nm. The spectra results showed that co-doped with Na+ ions could break the clusters of Yb3+ ions and modulate the spectroscopy properties of Yb3+: CaF2 lattice efficiently. This paper proved that doping with NaF is an efficient strategy to improve the transmittance and fluorescence quantum efficiency of Yb3+:CaF2 transparent ceramics.