Er ³⁺ /Yb ³⁺ co‐doped oxyfluoro tellurite glasses: Analysis of optical temperature sensing based on up‐conversion luminescence

Abstract The effect of Yb ³⁺ co‐doping on relaxation dynamics of excited states of Er ³⁺ ion in oxyfluoro tellurite (TZYN) glasses was demonstrated employing excitation and luminescence spectroscopy. The up‐conversion luminescence spectra were studied as a function of temperature in the 298–633 K range, and fluorescence intensity ratio (FIR) for green bands due to the ² H _11/2 → ⁴ I _15/2 and ⁴ S _3/2 → ⁴ I _15/2 transitions of Er ³⁺ ion against temperature was determined. The temperature sensing performance of TZYN:Er ³⁺ /Yb ³⁺ glasses was studied using the FIR technique up to 633 K. The maximum absolute ( S _a ) and relative ( S _r ) sensitivity of 0.00246 K ⁻¹ at 413 K and 0.72% K ⁻¹ at 323 K, respectively, were determined for TZYN:0.5Er ³⁺ /1.0 Yb ³⁺ glass.