Dual and chiral objects for optical activity in general scattering directions

TL;DR

This paper introduces a novel design of chiral, electromagnetically dual scatterers that preserve light helicity, enabling optical activity in all scattering directions, advancing the development of optically active artificial structures.

Contribution

It demonstrates that a unit cell composed of chiral, dual electromagnetic scatterers can achieve optical activity in all scattering directions, a previously unconsidered condition.

Findings

Optical activity demonstrated in general scattering directions.

Chiral dual scatterers preserve light helicity.

New design enhances artificial optical activity.

Abstract

Optically active artificial structures have attracted tremendous research attention. Such structures must meet two requirements: Lack of spatial inversion symmetries and, a condition usually not explicitly considered, the structure shall preserve the helicity of light, which implies that there must be a vanishing coupling between the states of opposite polarization handedness among incident and scattered plane waves. Here, we put forward and demonstrate that a unit cell made from chiraly arranged electromagnetically dual scatterers serves exactly this purpose. We prove this by demonstrating optical activity of such unit cell in general scattering directions.