Optical properties and upconversion in Er3+ and Ho3+ doped in lithium tellurite glass

Ho3+ and Er3+ doped lithium tellurite glasses have been formed with different concentrations of rare earth and their optical properties are derived on the basis of their absorption and fluorescence spectra. Intense upconversion emission in ultraviolet/violet, green and red regions have been observed when these glasses are pumped with NIR radiation. A preliminary study indicates that they can be used as temperature sensors.