The effect of In~(3+) ion on the optical characteristics of Er~(3+) in Er/Yb: LiNbO_3 crystal

摘要

The effect of In~(3+) ion on the optical characteristics of Er~(3+) ion in Er/Yb:LiNbO_3 crystal under 980 nm excitation has been investigated. The Er and Yb contents in the crystals were measured by an inductively coupled plasma atomic emission spectrometer (ICP-AES). A significant enhancement of 1.54 μm emission was observed for Er/Yb:LiNbO_3 crystal doped with 1 mol% In_2O_3. The studies on the UV-vis absorption and the OH~- absorption spectra indicate that the threshold concentration of In~(3+) ion decreases with the Er/Yb doping in Er/Yb/In:LiNbO_3 crystal. The 1 mol% In_2O_3 doping results in the reduction of absorption cross section in the UV-vis region, meaning the formation of Er~(3+) cluster sites. The enhancement of 1.54 μm emission is attributed to the larger probabilities of the cross relaxation processes ~4S_(3/2) + ~4I_(15/2)→ ~4I_(9/2) + ~4I_(13/2) (Er), ~4S_(3/2) + ~4I_(15/2) - ~4I_(13/2) + ~4I_(9/2) (Er) and ~4I_(9/2) +~ 4I_(15/2) - ~4I_(13/2) + ~4I_(13/2) (Er) induced by Er~(3+) cluster sites.