Separation of a Toroidal Mode in Clusters of Dielectric Particles

authored by

Tong Wu, Andrey B. Evlyukhin, Vladimir R. Tuz

Abstract

Constructing and utilizing toroidal modes in clusters of dielectric particles opens pathways to creating more efficient, compact, and functional devices across various fields, from sensing and telecommunications to energy and defense applications. Toroidal modes contribute to unusual material properties related to artificial magnetism, which is essential for designing innovative metamaterials. In this paper, we establish a relationship between eigenoscillations (modes) and scattering characteristics of a toroidal dielectric particle (torus) and clusters of particles composed of different numbers of dielectric disks arranged in a circular configuration (rings) in terms of the manifestation of their toroidal response. In particular, we examine the multipole contributions to the scattering cross-sections obtained in the exact form and long-wavelength approximation. A toroidal mode is introduced as a mode of the system for which the second-order term related to the exact electric dipole in the multipole decomposition is much greater than the first-order term. We show that the individual modes of the torus and hybrid modes of the ring consisting of an electromagnetically coupled ensemble of particles can be uniquely related, including the lowest-frequency toroidal dipole mode. Unlike the torus, the toroidal dipole mode in the ring can be separated in frequency from other multipole contributions, allowing excitation of the pure toroidal dipole resonance when providing corresponding irradiation conditions for external electromagnetic waves. This study provides an opportunity to better understand the physics of toroidal resonances in structures containing ensembles of dielectric particles and the peculiarities of their application in advanced microwave and photonic systems.

Organisation(s)

PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Institute of Quantum Optics

External Organisation(s)

Jilin University
Kharkov National University

Type

Article

Journal

Progress in Electromagnetics Research

Volume

180

Pages

103-113

No. of pages

11

ISSN

1070-4698

Publication date

17.12.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Radiation, Condensed Matter Physics, Electrical and Electronic Engineering

Electronic version(s)

https://doi.org/10.2528/PIER24110606 (Access: Open)