Theoretical and experimental behavior of optical properties of Er3+ doped fluoroaluminate glasses

The study of a new composition of fluoride glasses based on a mixed fluoroaluminate matrix with small additives of phosphates was carried out. Advanced thermal stability Delta T of the initial glassy matrix, exceeding the classical fluoride systems, was established from the difference between the glass transition temperatures and the onset of crystallization (Delta T = 108 degrees C). Refractive index dispersion was obtained based on the Sellmeier equations. The radiative characteristics of fluoroaluminate glass samples with different erbium contents were studied in order to evaluate the efficiency of luminescence in the visible and near IR regions. It was found that the theoretical and experimental values of the luminescence lifetimes of energy levels H-2(11/2), S-4(3/2), F-4(9/2) and I-4(13/2) depend on the concentration of erbium ions. The effect of concentration quenching of upconversion luminescence bands was found; for near infrared emission around 1.5 mu m the quantum efficiency was 96 % in the absence of luminescence quenching.