Optical properties of thulium-doped chalcogenide glasses and the uncertainty of the calculated radiative lifetimes using the Judd-Ofelt approach

A brief description of the basic spectroscopic properties of Tm3+ -doped 20Ge-5Ga-10Sb-65S (GeGaSbS) glass is presented. Spontaneous-emission probabilities, radiative lifetimes, branching ratios, and quantum efficiency of Tm3+ in GeGaSbS glass are evaluated by use of Judd-Ofelt theory. Lifetime measurements are carried out at room and low temperatures. A large difference of the lifetime values occurs between the theoretical and experimental results. McCumber and Ladenburg-Funchtbauer techniques are used for the emission cross-section determinations. Discrepancies appear between these two techniques. Hypotheses about the presence of the diffusion-limited relaxation process are applied for explanations.