Er3+ local structure and its optical properties in ZnO–PbO tellurite glasses

Erbium doped tellurite glasses (TPE), having composition (70TeO2–(30 − x)ZnO–xPbO)0.99–(Er2O3)0.01 (x = 5, 10, 15, and 20), were prepared by melt quenching technique and characterized by density measurements, Raman and optical spectroscopies and extended X-ray absorption fine structure (EXAFS) experiments. The main structural modifications of glasses as a function of the PbO/ZnO ratio are monitored by Raman scattering. EXAFS analysis shows almost unchanged short range environment around Er3+ ions for all glasses. Absorption and luminescence spectra evidence a significant decrease of the asymmetry of crystal field at the Er3+ ion site as the PbO content increases.