Optical spectroscopy of Tm3+ ions in GeO2-PbO-Nb2O5 glasses

In this work, we report the optical properties of Tm3+ doped lead-niobium-germanate glasses (GeO2-PbO-Nb2O5) for different Tm3+ concentrations ranging between 0.5 and 3 wt%. Judd-Ofelt intensity parameters have been determined to calculate the radiative transition probabilities and radiative lifetimes of excited states. Luminescence spectra and lifetimes were measured under 798 nm excitation. The infrared emissions at 1474 nm and 1820 nm have been characterized at room temperature for all concentrations. In this glass the infrared emission corresponding to the 3H4 → 3F4 transition is broader by nearly 40 nm if compared to fluoride glasses used for S-band amplifiers. The stimulated emission cross-sections have been determined from the line shape of the emission spectra and the lifetimes of levels 3H4 and 3F4 respectively.