Erbium-doped sodium-lead and tungsten-lead metaphosphate glasses for temperature sensing

Frequency upconversion emission (UC) in visible region from Er³⁺-doped materials have been intensively investigated in the last decades and employed in the development of photonic devices such as temperature sensors. Among the multitude of potential hosts, phosphate glasses are promising materials for this purpose due to their physical properties such as large thermal expansion coefficient, low melting temperatures, high transparency in the UV range and efficient infrared-to-visible UC. In this work, we investigate the use of Er³⁺-doped tungsten-lead and sodium-lead-metaphosphate glasses as temperature sensors, based on the fluorescence intensity ratio technique.