TY - JOUR

T1 - Separation of a Toroidal Mode in Clusters of Dielectric Particles

AU - Wu, Tong

AU - Evlyukhin, Andrey B.

AU - Tuz, Vladimir R.

N1 - Publisher Copyright: © 2024, Electromagnetics Academy. All rights reserved.

PY - 2024/12/17

Y1 - 2024/12/17

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85213295842&partnerID=8YFLogxK

U2 - 10.2528/PIER24110606

DO - 10.2528/PIER24110606

M3 - Article

AN - SCOPUS:85213295842

VL - 180

SP - 103

EP - 113

JO - Progress in Electromagnetics Research

JF - Progress in Electromagnetics Research

SN - 1070-4698

ER -