Investigation of Up Conversion Emissions of Er³⁺/Yb³⁺ Codoped TeO₂-B₂O₃-Nb₂O₅-ZnO-WO₃-TiO₂ Glass Systems for Optical Thermometry

Abstract

The conventional melt quenching technique was used to create Er3+/Yb3+ doped TeO2-B2O3-Nb2O5-ZnO-WO3-TiO2 glasses. The upconversion luminescence characteristics of the glasses were examined under 975 nm laser excitation at different powers. Luminescence intensities increased with increasing pump power until a certain power value was reached, at which point they declined. Lower pump power levels resulted in stronger green emissions, while higher pump power values resulted in stronger red emissions. The intensity-power curve was used to compute the number of transition photons. The calculations show that the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions are based the sequential absorption of two photons. With increased pump power, the (x, y) color coordinates shifted from green to red on the CIE diagram. The glasses' temperature-dependent luminescence was obtained. The intensity ratio approach was used to calculate the temperature sensitivity of the glasses. Maximum absolute sensitivity was found to be 0.0032 K-1 at 560 K for the TeO2 based glass with 1.25 mol% Er3+.