Influence of Eu³⁺ ions on 1.5 µm luminescence of Er³⁺ in TeO₂–ZnO–Bi₂O₃ glasses

Abstract

TeO2–ZnO–Bi2O3 glasses doped with Eu3+ and Er3+ ions were prepared and investigated for their physical, optical, and luminescent properties. The optical band gap is calculated for the indirect transition and is within the 3.04–3.10 eV range. The Urbach energy varies from 0.135 to 0.098 eV with the increase in Eu3+ compound content. Bi2Te2O8 and ZnTeO3 complex oxide phases are generated in the mixture as intermediate compounds in the course of charge thermal processing. The additional doping of TeO2–ZnO–Bi2O3:Er3+ glass samples with Eu3+ ions is shown to lead to the appearance of cross-relaxation channels of the Er3+ ion states and decreases the population of the 4I13/2 state of the Er3+ ions. Simultaneously, the excited 4I11/2 state of the Er3+ ions is also subjected to strong cross-relaxation decay. The Eu3+ ions are shown to decrease the 4I13/2 level population of Er3+ ions, which may facilitate the attainment of population inversion if the 4I13/2 level is at the lower level of the laser transition.