Spectral characteristics and optical temperature sensing properties of Er3+/Yb3+-co-doped phosphate glasses with GeO2 modification.

Abstract

Er3+/Yb3+-co-doped phosphate glasses with GeO2 modification (PLAZGs) were successfully prepared by the melt-quenching method. The phenomenological intensity parameters Ωt (t=2, 4, 6) of the PLAZGs have been calculated by the Judd-Ofelt theory. Based on the phenomenological intensity parameters, the spectroscopic parameters of Er3+ and fluorescence intensity ratio (FIR) of green upconversion emissions were estimated. It was observed that, under 980 nm excitation, all samples exhibit green and red upconversion emissions of Er3+. The 10 mol% GeO2 modified phosphate glass has the strongest upconversion emission. Additionally, the fluorescence decays of the 2F5/2→2F7/2 transition of Yb3+ ions were measured to evaluate the energy transfer efficiency from Yb3+ to Er3+ ions. Finally, the optical temperature sensing properties based on upconversion emissions were investigated at temperatures from 150 K to 600 K. The maximum absolute temperature sensitivity S value of 6.0×10-3K-1 at 400 K is obtained, which indicates that the glass is promising for temperature sensing application based on the FIR technology.