Material-independent modes for electromagnetic scattering

TL;DR

This paper introduces a permittivity-independent eigenmode representation for electromagnetic scattering, enabling analysis and design of scattering properties of dielectric objects regardless of their permittivity.

Contribution

It presents a novel eigenmode framework that separates geometry from permittivity, facilitating tailored scattering analysis and design for arbitrary-shaped dielectric objects.

Findings

Eigenmode expansion coefficients are rational functions of permittivity.

The approach highlights plasmonic and photonic modes in scattering.

Application demonstrated on dielectric sphere analysis and design.

Abstract

In this Letter, we introduce a representation of the electromagnetic field for the analysis and synthesis of the full-wave scattering by a homogeneous dielectric object of arbitrary shape in terms of a set of eigenmodes independent of its permittivity. The expansion coefficients are rational functions of the permittivity. This approach naturally highlights the role of plasmonic and photonic modes in any scattering process and suggests a straightforward methodology to design the permittivity of the object to pursue a prescribed tailoring of the scattered field. We discuss in depth the application of the proposed approach to the analysis and design of the scattering properties of a dielectric sphere.