Effect of hydroxyl groups on nonradiative decay of Er3+ : 4I13 / 2 → 4I15 / 2 transition in zinc tellurite glasses

A series of zinc tellurite glasses of 75TeO2–20ZnO–(5 − x)La2O3–xEr2O3 (x = 0.02, 0.05, and 0.1 mol%) with the different hydroxl groups were prepared by the conventional melt-quenching method. Infrared spectra were measured in order to estimate the exact content of OH− groups in samples. The observed increase of the fluorescence lifetime with the oxygen bubbling time has been related to the reduction in the OH− content concentration as evidenced by IR transmission spectra. Various nonradiative decay rates from 4I13 / 2 of Er3+ with the change of OH content were determined from the fluorescence lifetime and radiative decay rates were calculated on the basis of Judd–Ofelt theory.