Due to the favorable thermal properties of sesquioxides as hosts for rare earth laser ions, we have recently studied the spectroscopy of Er:Lu₂O₃ in the 1400-1700 nm wavelength range, and here report its comparison with our earlier results on Er:Y₂O₃ and Er:Sc₂O₃. These studies include absorption and fluorescence spectra, fluorescence lifetimes, and inference of absorption and stimulated emission cross sections, all as a function of temperature. At room temperature, optical absorption limits practical laser operation to wavelengths longer than about 1620 nm. In that spectral range, the strongest stimulated emission peak is that at 1665 nm in Er:Sc₂O₃, with an effective cross section considerably larger than those of Er:Y₂O₃ and Er:Lu₂O₃. At 77K, the absorption is weak enough for efficient laser operation at considerably shorter wavelengths, where there are peaks with much larger stimulated emission cross sections. The three hosts all have peaks near 1575-1580 nm with comparably strong cross sections. As we have reported earlier, it is possible to lase even shorter wavelengths efficiently at this temperature, in particular the line at 1558 nm in Er:Sc₂O₃. Our new spectroscopic studies of Er:Lu₂O₃ indicate that its corresponding peak, like that of Er:Sc₂O₃, has a less favorable ratio of stimulated emission to absorption cross sections. Reasons for the differences will be discussed. We conclude that for most operating scenarios, Er:Sc₂O₃ is the most promising of the Er-doped sesquioxides studied for laser operation around 1.5-1.6 microns.

Date Published: 23 May 2013
PDF: 8 pages
Proc. SPIE 8733, Laser Technology for Defense and Security IX, 87330H (23 May 2013); doi: 10.1117/12.2017873

Published in SPIE Proceedings Vol. 8733:
Laser Technology for Defense and Security IX
Mark Dubinskii; Stephen G. Post, Editor(s)