Induced changes in the refractive index of LiNbO3 crystals through Sc2O3 doping

The dependence of the ordinary (n(o)) and extraordinary (n(e)) refractive indices in congruent Sc2O3-doped LiNbO3 crystals are reported. The Sc3+ ion concentrations in the crystals were varied from 0% to 7%. It has been found that n(o) shows a clear singularity for a Sc3+ ion concentration of 3%. The experimental data of n(o) and n(e) are described by a generalised Sellmeier equation, which takes into account different Sc3+ ions sites location in the host matrix. Additionally, the role of the Sc2O3 content in the intrinsic defect distribution in LiNbO3 crystals has been studied by using Cr3+ ions as an EPR probe. (C)2002 Elsevier Science B.V. All rights reserved.