Temperature sensing down to 4 K with erbium-doped tellurite glasses

Abstract

Two binary tellurite glasses within TeO2–PbCl2–WO3 system with different concentrations of Er3+ ions were prepared by the conventional melt-quench technique and their optical properties were compared with emphasis on their potential use for temperature sensing starting from 4 K. Therefore, absorption and emission spectroscopy was used to determine the emission properties of Er3+ in the visible and near-infrared regions across a wide temperature range of 4-300 K. Photoluminescence emissions resulting from direct absorption or frequency up-conversion were measured across a wide temperature range and their dependence on the concentration of erbium ions and on excitation power density were studied in detail. It was demonstrated that by optimizing concentration of erbium ions, the luminescence intensity ratio of suitably selected thermally coupled/uncoupled levels and their Stark sublevels can be used for the non-contact optical temperature sensing at cryogenic temperatures.