Upconversion Emission of Infrared Excited Er~(3+)-Doped Transparent Glass Ceramics Containing CaF_2 Nano-Crystals

摘要

Upconversion luminescence of Er~(3+)-doped SiO_2-Al_2O_3-CaO-NaF-CaF_2 transparent glass ceramics under 980 nm excitation was investigated. XRD and TEM experiments revealed the homogeneous distribution of CaF_2 nano-crystals among the glassy matrix. Intense red upconversion signal was recorded and its intensity increased with the increasing of heating temperature and Er~(3+)-doping level at the range of 0.1 to 1.0 mol%. When Er~(3+)doping reached 2 mol%, the concentration quenching effect appeared. All these results could be due to the incorporation of Er~(3+) ions into precipitated CaF_2 nano-crystals. The quadratic pump power dependence of the upconversion luminescence intensity indicated that the transition mechanism of the red emission was due to two-photon absorption processes.