Spectroscopic analysis of Er super(3+):Y sub(2) O sub(3) relevant to 2.7[mu]m mid-IR laser

The spectroscopic properties of ceramic Er super(3+):Y sub(2) O sub(3) relevant to the 2.7 [mu]m 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 super(4) I sub(11/2) 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 Er super(3+):Y sub(2) O sub(3) laser parameters for the mid-IR ~2.7um transition are presented as well.