Minimizing the scattering of a non-magnetic cloak

TL;DR

This paper investigates the electromagnetic scattering properties of a nonmagnetic cloak designed for optical invisibility, demonstrating that thin, impedance-mismatched cloaks can effectively reduce total scattering.

Contribution

It proposes an approximation for an ideal nonmagnetic cloak and analyzes its scattering characteristics, highlighting the effects of thickness and impedance matching.

Findings

Thinner cloaks increase forward scattering dramatically.

Impedance mismatch allows effective scattering reduction.

Directional scattering control is possible.

Abstract

Nonmagnetic cloak offers a feasible way to achieve invisibility at optical frequencies using materials with only electric responses. In this letter, we suggest an approximation of the ideal nonmagnetic cloak and quantitatively study its electromagnetic characteristics using a full-wave scattering theory. It is demonstrated that the forward scattering of the impedance matched cloak increases dramatically as the thickness of the cloak decreases. Nevertheless, it is still possible to effectively reduce the total scattering cross section with a very thin cloak whose impedance is not matched to the surrounding material at the outer boundary. Our analysis also provides the flexibility of reducing the scattering in an arbitrary direction.