Site characterization of rare-earth-doped LiNbO3 using total site selective spectroscopy

Abstract

A technique, total site selective spectroscopy, is presented to optically identify spectroscopic sites in Er:LiNbO3. Six sites are seen; four major nonclustered sites and two minor cluster sites. When pumping the 4F9/2 manifold at low temperatures (∼12 K), only cluster sites are found to upconvert using a nonradiative energy transfer mechanism. The polarization of Er3+ absorption cross sections are shown to be site dependent while the manifold lines from different sites are highly degenerate. These characteristics likely contribute to the observed simultaneous lasing at two wavelengths of devices based in this medium.