Scattering and absorption invariance of nonmagnetic particles under duality transformations

TL;DR

This paper demonstrates that the total scattering, including extinction, scattering, and absorption, by nonmagnetic particle clusters remains invariant under electromagnetic duality transformations, revealing fundamental symmetry properties.

Contribution

It reveals that total scattering properties of nonmagnetic particles are invariant under duality transformations, establishing a new symmetry perspective in scattering analysis.

Findings

Total scattering properties are duality-invariant.

Self-dual clusters are polarization-independent.

Duality-connected configurations have identical scattering.

Abstract

We revisit the total scatterings (in terms of extinction, scattering and absorption cross sections) by arbitrary clusters of nonmagnetic particles that support optically-induced magnetic responses. Our reexamination is conducted from the perspective of the electromagnetic duality symmetry, and it is revealed that all total scattering properties are invariant under duality transformations. This secures that for self-dual particle clusters, the total scattering properties are polarization independent for any fixed incident direction; while for non-self-dual particle clusters, two scattering configurations that are connected to each other through a duality transformation would exhibit identical scattering properties. This electromagnetic duality induced invariance is irrelevant to specific particle distributions or wave incident directions, which is illustrated for both random and periodic clusters.