Judd-Ofelt analysis and experimental spectroscopic study of erbium doped phosphate glasses

A series of phosphate glasses including two compositions that are similar to commercial laser glasses and 3 new compositions doped with 2 × 1020 Er3+/cm3 were prepared by using the classical melt quenching technique. The new glass compositions show much better glass forming properties than the commercially available glasses, lower molecular weights and lower optical basicities which are expected to be advantageous for their luminescence and laser properties. From the UV-vis-NIR absorption spectra, detailed Judd-Ofelt analyses were conducted and the radiative properties of the luminescent levels of Er3+ in these host materials were calculated. In fact all three compositions show longer calculated luminescence lifetimes than the compositions that are based on commercially available laser glasses. The absorption and the emission cross sections, the luminescence lifetimes and the quantum efficiency at 1530 nm were investigated. LiZnLaAPF glass can be suggested as a good host to generate efficient lasing action at 1530 nm. The variation of the Judd-Ofelt intensity parameters Ω2, Ω4 and Ω6 is discussed with respect to the glass compositions and their properties. For this, the calculated Ω2, Ω4 and Ω6 values are compared to the results of numerous publications on Er3+ doped phosphate glasses. From this data a correlation with the symmetry at the local rare earth site (Ω2) and with the theoretical optical basicity (Ω6) of the glass composition can be assumed.