Thermal stability and spectroscopic properties of Eu-doped phosphate glasses for lasing applications

Current study is aimed at evaluating Eu-doped barium -bismuth phosphate glasses as potential visible laser medium operating in red spectral region. Samples with composition xEu2O3-20BaO-20Bi2O3-1.5Al2O3-(58.5-x) P2O5 (x = 0, 0.5, 1.0, 1.5) were prepared using melt -quenching technique. Physical parameters, such as, density, molar volume, oxygen packing density, rare-earth ion concentration, inter -nuclear distance and field strength were evaluated. Thermal stability of prepared glass samples was observed using Thermogravimetric Analysis (TG). The influence of rare-earth oxide content on glass transition temperature Tg, crystallization temperature Tc and onset of crystallization temperature Tx was studied through Differential Thermal Analysis (DTA). Optical band gap and related optical properties were evaluated from absorption spectrum recorded in the range 225-1000 nm. Judd-Ofelt parameters, branching ratio, radiative lifetime, emission cross-section and other radiative properties were evaluated from photoluminescence emission spectrum in the range 500-750 nm. High value of emission cross-section observed for transition 5D0 -> 7F4 in 0.5-EuBiPBa sample signifies its potential use in the development of visible lasers.