Induced changes in the refractive index of LiNbO_3 crystals through Sc_2O_3 doping

摘要

The dependence of the ordinary (n_o) and extraordinary (n_e) refractive indices in congruent Sc_2O_3-doped LiNbO_3 crystals are reported. The Sc~3+ ion concentrations in the crystals were varied from 0/100 to 7/100. It has been found that n_o shows a clear singularity for a Sc~3+ ion concentration of 3/100. The experimental data of n_o and n_e are described by a generalised Sellmeier equation, which takes into account different Sc~3_+ ions sites loation in the host matrix. Additionally, the role of the Sc_2O_3 content in the intrinsic defect distribution in liNbO_3 crystals has been studied by using Cr~3+ ions as an EPR.