Spectroscopic characterization and temperature-dependent upconversion behavior of Er 3+ and Yb 3+ co-doped zinc phosphate glass

Abstract The zinc phosphate glass co-doped with Er 3+ and Yb 3+ ions was prepared by melt-quenching method. The Judd-Ofelt theory has been applied to analyze the absorption spectrum and estimate the spectroscopic parameters of Er 3+ ions. Upconversion luminescence of the glass was investigated under the excitation at 976 nm. The red and green emissions of Er 3+ ions were observed. The energy transfer processes between Yb 3+ and Er 3+ ions responsible for the upconversion emissions were discussed based on their dependences on pump power. The fluorescence decays of the relevant energy levels were measured for evaluating the energy transfer efficiency. Furthermore, the influence of temperature on upconversion emission in this glass was carried out at temperatures from 323 to 573 K. The result indicates that the glass has a potential application in the construction of optical temperature sensors based on the self-referenced FIR technique.