Tunable scattering cancellation of light using anisotropic cylindrical cavities

TL;DR

This paper investigates the limits and mechanisms of light scattering cancellation using anisotropic cylindrical cavities, revealing the role of Fano resonances in tunable invisibility in the visible spectrum.

Contribution

It analyzes the validity of invisibility conditions in hyperbolic nanotubes and demonstrates the role of Fano resonances in achieving tunable scattering suppression.

Findings

Invisibility relies on epsilon near zero in permittivity tensor components.

Fano resonances enable dramatic scattering reduction.

Tunable windows of invisibility are identified through resonance analysis.

Abstract

Engineered core-shell cylinders are good candidates for applications in invisibility and cloaking.In particular, hyperbolic nanotubes demonstrate tunable ultra-low scattering cross section in the visible spectral range. In this work we investigate the limits of validity of the condition for invisibility, which was shown to rely on reaching an epsilon near zero in one of the components of the effective permittivity tensor of the anisotropic metamaterial cavity. For incident light polarized perpendicularly to the scatterer axis, critical deviations are found in low-birefringent arrangements and also with high-index cores. We demonstrate that the ability of anisotropic metallodielectric nanocavities to dramatically reduce the scattered light is associated with a multiple Fano-resonance phenomenon. We extensively explore such resonant effect to identify tunable windows of invisibility.