Controlling the dispersion of longitudinal waves via the affine deformation of the interlaced wire medium

TL;DR

This paper investigates how affine deformation of double interlaced wire metamaterials influences their dispersion properties, revealing support for longitudinal eigenmodes and unique isofrequency surface shapes.

Contribution

It introduces a method to control dispersion in wire metamaterials through affine deformation, highlighting the impact on eigenmodes and isofrequency surface geometry.

Findings

Support for longitudinal eigenmodes at low frequencies across all deformations

Isofrequency surfaces are centered at Brillouin zone edges and shaped as ellipsoids

Analytical and numerical analysis of refractive indices

Abstract

We studied the dispersion properties of double interlaced wire metamaterials with geometry modified by affine transformation. That metamaterials were found to support eigenmodes with longitudinal polarization at low frequencies for all deformations. Due to the spatial dispersion the metamaterials isofrequency surfaces are centered at the Brillouin zone edges (rather than at $\Gamma$-point) and have the shape of ellipsoids. The refractive indices corresponding to the ellipsoids were analyzed both analytically and numerically.