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

Abstract TeO 2 –ZnO–Bi 2 O 3 glasses doped with Eu 3+ and Er 3+ 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 Eu 3+ compound content. Bi 2 Te 2 O 8 and ZnTeO 3 complex oxide phases are generated in the mixture as intermediate compounds in the course of charge thermal processing. The additional doping of TeO 2 –ZnO–Bi 2 O 3 :Er 3+ glass samples with Eu 3+ ions is shown to lead to the appearance of cross-relaxation channels of the Er 3+ ion states and decreases the population of the 4 I 13/2 state of the Er 3+ ions. Simultaneously, the excited 4 I 11/2 state of the Er 3+ ions is also subjected to strong cross-relaxation decay. The Eu 3+ ions are shown to decrease the 4 I 13/2 level population of Er 3+ ions, which may facilitate the attainment of population inversion if the 4 I 13/2 level is at the lower level of the laser transition.