Electromagnetic energy within single-resonance chiral metamaterial spheres

TL;DR

This paper derives an exact formula for electromagnetic energy inside a chiral metamaterial sphere, revealing how strong chirality can enhance internal fields even off-resonance, with implications for designing advanced optical materials.

Contribution

It provides a novel analytical expression linking internal electromagnetic fields and absorption in chiral metamaterial spheres, considering magnetic and chiral dispersive properties.

Findings

Strong chirality causes off-resonance field enhancement.

Derived explicit relation between internal fields and absorption cross-section.

Applied theory to demonstrate field enhancement in weakly absorbing spheres.

Abstract

We derive an exact expression for the time-averaged electromagnetic energy inside a chiral dispersive sphere irradiated by a plane wave. The dispersion relations correspond to a chiral metamaterial consisting of uncoupled single-resonance helical resonators. Using a field decomposition scheme and a general expression for the electromagnetic energy density in bi-anisotropic media, we calculate the Lorenz-Mie solution for the internal fields in a medium that is simultaneously magnetic and chiral. We also obtain an explicit analytical relation between the internal electromagnetic field and the absorption cross-section. This result is applied to demonstrate that strong chirality leads to an off-resonance field enhancement within weakly absorb.ing spheres.