Optical transitions and upconversion luminescence of Er3+-doped tellurite glass

Spectroscopic properties of Er3+-doped TeO2-WO3-Bi2O3 (TWB) glass has been investigated. The transition probabilities, excited state lifetimes, and the branching ratios have been predicted for Er3+ based on the Judd-Ofelt theory. The lifetime of 4I11/2 and 4I13/2 level were measured from time-resolved fluorescence decay. The mutiphonon relaxation of 4I11/2→4I13/2 transition in TWB glass was predicted and compared with other glass hosts. Efficient green and weak red upconversion luminescence from Er3+ centers in the glass sample was observed at room temperature, and the upconversion excitation processes have been analyzed.