Judd–Ofelt analysis of the $Er3+(4f11)$ absorption intensities in phosphate glass: $Er3+,$ $Yb3+$

A spectroscopic Judd–Ofelt investigation has been performed on $Er3+$ in the doubly doped phosphate $glass:Er3+,$ $Yb3+$ in order to assess its potential as a laser system. The standard Judd–Ofelt model was applied to the room-temperature absorption intensities of $Er3+(4f11)$ transitions to determine the intensity parameters: $Ω2=6.28×10−20$ $cm2,$ $Ω4=1.03×10−20$ $cm2,$ and $Ω6=1.39×10−20$ $cm2$ in the phosphate glass host. The intensity parameters are used to determine the radiative decay rates (emission probabilities of transitions) and branching ratios of the $Er3+$ transitions from the excited-state J manifolds to the lower-lying $J′$ manifolds. The radiative lifetimes of these excited states are determined from the radiative decay rates. The predicted decay rates and radiative lifetimes are compared to those of $Er3+$ transitions in other glass hosts. The quantum efficiency of the eye-safe laser transition $I13/24→4I15/2$ (1.54 μm) of $Er3+$ is approximately 80% in the phosphate glass host.