Optical toroidal dipolar response by an asymmetric double-bar metamaterial

TL;DR

This paper demonstrates the realization of an optical toroidal dipolar response using an asymmetric double-bar metamaterial, showing dominance over other moments and potential for novel optical phenomena.

Contribution

It introduces a novel nanostructured metamaterial design that enables the optical toroidal dipolar response in the visible regime.

Findings

Optical toroidal dipolar moment dominates over other moments.

Strong E-field confinement at the toroid center.

Resonance-enhanced optical response suitable for experiments.

Abstract

We demonstrate that the toroidal dipolar response can be realized in the optical regime by designing a feasible nanostructured metamaterial, comprising asymmetric double-bar magnetic resonators assembled into a toroid-like configuration. It is confirmed numerically that an optical toroidal dipolar moment dominates over other moments. This response is characterized by a strong confinement of an E-field component at the toroid center, oriented perpendicular to the H-vortex plane. The resonance-enhanced optical toroidal response can provide an experimental avenue for various interesting optical phenomena associated with the elusive toroidal moment.