Optical properties, concentration and thermal quenching of luminescence of Dy3+- doped La2O3-Na2O-ZnO-TeO2 glasses

Tellurite glasses of the chemical composition: xDy2O3-(7-x)La2O3-3Na2O-25ZnO-65TeO2, where (0 < x <= 7) were obtained by the melt quenching technique. The spectroscopic characteristic of Dy3+- doped title glasses was carried out based on absorption and luminescence spectra as well as luminescence decay kinetics measurements. The Judd-Ofelt intensity parameters omega lambda (lambda= 2, 4, 6) have been evaluated from the absorption spectrum and subsequently used to calculate the spontaneous emission probabilities, luminescence branching ratios and radiative lifetime of 4F9/2 emitting level of Dy3+. The emission cross-sections for Dy3+ transitions in the visible range have been determined applying Fuchtbauer-Ladenburg formula. The luminescence decay measurements revealed strong concentration quenching of Dy3+ emission. The non-exponential decay curves have been fitted in the frame of Inokuti-Hirayma model, indicating that the dipole-dipole interaction plays an important role in luminescence quenching of 4F9/2 level. The temperature dependence of luminescence decay times of 4F9/2 state of Dy3+ has been investigated.