The effect of In3+ ion on the optical characteristics of Er3+ in Er/Yb:LiNbO3 crystal

Abstract 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 2 O 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 2 O 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 4 S 3/2 + 4 I 15/2 → 4 I 9/2 + 4 I 13/2 (Er), 4 S 3/2 + 4 I 15/2 → 4 I 13/2 + 4 I 9/2 (Er) and 4 I 9/2 + 4 I 15/2 → 4 I 13/2 + 4 I 13/2 (Er) induced by Er 3+ cluster sites.