In this work, we have used the thermal lens technique combined with conventional
spectroscopy to characterize the thermo-optical properties of Er 3+-doped lead
pyrophosphate-based glasses. More precisely, we have investigated and quantified
experimentally the fluorescence quantum efficiencies of the Er 3+ levels, and we describe
the role of concentration quenching effects. The fluorescence quantum efficiency of the 4 I
13/2 level is very high when compared to other phosphate glasses, while that of the green …