Sensitive optical temperature sensor based on up-conversion luminescence spectra of Er3+ ions in PbO–Ga2O3–XO2 (X = Ge, Si) glasses

• Up-conversion of Er3+ ions in PbO–Ga2O3–XO2 (X = Ge, Si) glasses has been studied.
• Two-photon mechanism of up-conversion process was confirmed.
• Up-conversion luminescence spectra of Er3+ are changed with temperature.
• Fluorescence intensity ratios and maximum sensitivity parameters were determined.

Up-conversion luminescence spectra of Er3+ ions in PbO–Ga2O3–GeO2 and PbO–Ga2O3–SiO2 glasses have been examined as a function of temperature in the 298–650 K range. The relative emission intensities of green bands corresponding to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ were determined with temperature. Based on up-conversion luminescence spectra of Er3+, the fluorescence intensity ratio and temperature sensitivity for glasses based on PbO–Ga2O3–XO2 (X = Ge, Si) were calculated. The maximum sensitivity is equal to 20.4 × 10−4 K−1 at T = 620 K (X = Ge) and 26.4 × 10−4 K−1 at T = 590 K (X = Si) suggesting potential application in optical sensor thermometry.