Interplay between anisotropy and spatial dispersion in metamaterial waveguide

TL;DR

This paper investigates how anisotropy and spatial dispersion influence the waveguide modes of uniaxial anisotropic metamaterials, revealing their effects on mode degeneracy, density of states, and light propagation.

Contribution

It provides a detailed analysis of the interplay between anisotropy and spatial dispersion in metamaterial waveguides, highlighting their combined impact on mode spectrum and optical properties.

Findings

Spatial dispersion breaks the singularity in the density of optical states.

It suppresses negative dispersion caused by anisotropy.

Under certain conditions, light can be completely stopped.

Abstract

We analyze spectrum of waveguide modes of an arbitrary uniaxial anisotropic metamaterial slab with non-local electromagnetic response whose permittivity tensor could be described within Drude approximation. Spatial dispersion was introduced within the hydrodynamical model. Both anisotropy and spatial dispersion were considered as perturbations. This helps to distinguish their effect on the spectrum of the slab and to analyze lifting of the degeneracy of eigenmodes at plasma frequency in detail. Spatial dispersion is shown to result in break of the singularity in the den- sity of optical states in the hyperbolic regime and in suppression of negative dispersion induced by anisotropy. Mutual effect of spatial dispersion and anisotropy can bring light to a complete stop at certain frequencies.