Spectroscopic properties of Er3+-doped fluorotellurite glasses

In this work we report the spectroscopic properties of Er3+-doped fluorotellurite glasses in the 46.6TeO2–18.2ZnO–35.2ZnF2 system for different ErF3 concentrations between 0.5 and 3 wt%. Absorption and emission spectra and lifetimes have been measured in the visible and near infrared regions. Judd–Ofelt analysis has been performed to estimate the radiative transition probabilities. The high content of ZnF2 in this glass decreases the covalency degree in rare-earth site and results in a lower value of Ω2 if compared with zinc tellurite glasses. The infrared emissions at 1532 nm are broader by nearly 30 nm in these glasses if compared to silica glass. This broad emission together with the high values of the stimulated emission cross-section and lifetime of level 4I13/2 make these glasses attractive for broadband amplifiers. The decays from level 4I13/2 are single exponentials for all concentrations which indicates a fast energy diffusion between Er3+ ions. Similar values for the critical radius and energy transfer microparameter are obtained for the different concentrations, which supports the dipole–dipole transfer hypothesis.

► Broadband and high absorption and emission cross-sections for the 4I13/2 ↔ 4I15/2 transition.
► Long lifetimes of excited levels of Er3+ ions due to the high content of ZnF2.
► Energy transfer microparameter higher than those found in silicate and phosphate glasses.