Concentration quenching of the 1470 nm emission in Tm3+-doped lead-niobium-germanate glasses

In this work, we have studied the concentration quenching of the H-3(4)-> F-3(4) emission of Tm3+ doped lead-niobium-germanate glasses (GeO2-PbO-Nb2O5) for different Tm-3, concentrations (0.1, 0.2, 0.5, 1, 2, and 3 wt%). The emission spectra obtained under 798 nm excitation reveal the existence of energy transfer via cross-relaxation among Tm3+. As a result, the intensity of the infrared H-3(4)-> F-3(4) emission at 1474 rim decreases in relation to that of the 1820 nm emission as concentration increases. The non-exponential character of the decays from the H-3(4) level with increasing concentration, together with the dependence of the effective decay rates on Tm3+, concentration, indicate the presence of a dipole-dipole quenching process in the framework of a diffusion-limited regime.