Optical anisotropic metamaterials: Negative refraction and focusing

TL;DR

This paper designs 3D metallic nanowire media that act as effective anisotropic metamaterials with hyperbolic dispersion, enabling negative refraction and focusing effects in the long-wavelength limit.

Contribution

It introduces a method to model 3D metallic nanowire media as homogeneous indefinite anisotropic media with hyperbolic dispersion relations.

Findings

Effective permittivities are retrieved from dispersion relations.

Pseudo focusing matches that of a homogeneous medium.

Hyperbolic dispersion persists for evanescent modes.

Abstract

We design three-dimensional (3D) metallic nanowire media with different structures and numerically demonstrate that they can be homogeneous effective indefinite anisotropic media by showing that their dispersion relations are hyperbolic. For a finite slab, a nice fitting procedure is exploited to obtain the dispersion relations from which we retrieve the effective permittivities. The pseudo focusing for the real 3D wire medium agrees very well with the homogeneous medium having the effective permittivity tensor of the wire medium. Studies also show that in the long-wavelength limit, the hyperbolic dispersion relation of the 3D wire medium can be valid even for evanescent modes.