Spectral characteristics and optical temperature sensing properties of Er/Yb-co-doped phosphate glasses with GeO modification.

/-co-doped phosphate glasses with modification (PLAZGs) were successfully prepared by the melt-quenching method. The phenomenological intensity parameters (=2, 4, 6) of the PLAZGs have been calculated by the Judd-Ofelt theory. Based on the phenomenological intensity parameters, the spectroscopic parameters of 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 . The 10 mol% modified phosphate glass has the strongest upconversion emission. Additionally, the fluorescence decays of the → transition of ions were measured to evaluate the energy transfer efficiency from to 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 value of 6.0×10 at 400 K is obtained, which indicates that the glass is promising for temperature sensing application based on the FIR technology.