Surface Bloch waves in metamaterial and metal-dielectric superlattices

TL;DR

This paper investigates electromagnetic surface Bloch waves in periodic structures combining metamaterials and dielectrics, revealing unique propagation characteristics and a phenomenon called tri-refringence in subwavelength regimes.

Contribution

It derives dispersion relations for surface Bloch modes in metamaterial and metal-dielectric superlattices, highlighting new propagation features and tri-refringence effects.

Findings

Bulk modes exhibit tri-refringence in subwavelength regime

Surface modes can propagate parallel to the Bloch wavevector

Distinct dispersion relations for TE and TM polarizations

Abstract

We study the properties of electromagnetic Bloch waves in semi-infinite periodic structures created by alternating metamaterial and dielectric layers. We derive and analyze the dispersion relations in the long-wavelength limit for both TE- and TM-polarized surface Bloch modes, for magnetic metamaterials with negative refraction and metal-dielectric plasmonic superlattices. We reveal that in the subwavelength regime the bulk modes are characterized by three different refractive indices ("tri-refringence") while the surface modes can propagate parallel to the Bloch wavevector and along the interface between superlattice and semi-infinite dielectric.