We proposed a new approach to calculate the refractive indices of Mg-doped lithium niobate using generalized vacancy models combined with a ferroelectric phase transition theory. We have obtained a generalised Sellmeier equation which takes into account the defect structure and Mg-doped lithium niobate. A comparison between the calculated values from this approach and the experimental data of the temperature and refractive indices is detailed.We proposed a new approach to calculate the refractive indices of Mg-doped lithium niobate using generalized vacancy models combined with a ferroelectric phase transition theory. We have obtained a generalised Sellmeier equation which takes into account the defect structure and Mg-doped lithium niobate. A comparison between the calculated values from this approach and the experimental data of the temperature and refractive indices is detailed
