Spectroscopic analysis of Er^3+:Y_2O_3 relevant to 27µm mid-IR laser

The spectroscopic properties of ceramic Er3+:Y2O3 relevant to the 2.7 µm mid-IR laser transition were studied in the temperature range of 77–300K. We present the results of experimental measurements of absorption and fluorescence which were used to determine the branching ratios and fluorescence quantum efficiency of the 4I11/2 upper laser level. We have shown that the quantum yield of the mid-IR transition more than doubles when the sample is cooled from room to cryogenic temperature, and the stimulated emission cross-section of the highest peak increases by a factor of 10 for the same temperature change. Updated cryogenic Er3+:Y2O3 laser parameters for the mid-IR ~2.7um transition are presented as well.