Conditions for achieving invisibility of hyperbolic multilayered nanotubes

TL;DR

This paper investigates how edge effects influence the scattering and near-field behavior of hyperbolic multilayered nanotubes, revealing critical boundary layer roles and conditions for achieving invisibility.

Contribution

It provides a detailed analysis of edge effects in multilayered hyperbolic nanotubes, highlighting their impact on scattering spectra and near-field patterns, which was previously underestimated.

Findings

Edge effects significantly alter scattering spectra.

Dielectric layer contact with the cavity enhances scattering.

Boundary layers are crucial in resonant behavior.

Abstract

Highly-anisotropic plasmonic nanotubes exhibit a dramatic drop of the scattering cross section in the transition regime from hyperbolic to elliptic dispersion. The characterization of a realistic multilayered metamaterial is typically carried out by means of an effective medium approach providing average components of the permittivity tensor and wave fields. Here, the edge effects of the metal-dielectric stratified nanotube for different combinations were thoroughly analyzed. We show how the boundary layers, which in principle remain fully irrelevant in the estimation of the effective permittivity of the nanotube, however play a critical role in the resonant scattering spectra and the near field patterns. A remarkable enhancement of the scattered wave field is unexpectedly experienced at the frequencies of interest when a dielectric layer is chosen to be in contact with the cavity core.