Applicability of point-dipoles approximation to all-dielectric metamaterials

Abstract

All-dielectric metamaterials consisting of high-dielectric inclusions in a low-dielectric matrix are considered as a low-loss alternative to resonant metal-based metamaterials. In this paper we investigate the applicability of the point electric and magnetic dipoles approximation to dielectric meta-atoms on the example of a dielectric ring metamaterial. Despite the large electrical size of high-dielectric meta-atoms, the dipole approximation allows for accurate prediction of the metamaterials properties for the rings with diameters up to $\ensuremath{\approx}0.8$ of the lattice constant. The results provide important guidelines for design and optimization of all-dielectric metamaterials.