Toroidal dipole bound states in the continuum

He, Yuan; Guo, Guangtao; Feng, Tianhua; Xu, Yi; Miroshnichenko, Andrey E.

doi:10.1103/physrevb.98.161112

Cited by 218 publications

(130 citation statements)

References 67 publications

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“…One interesting type of BICs relies on the symmetry properties of both discrete mode and coexisted radiative continuum. When a discrete mode is characterized by a particular symmetry class, radiative continuum belonging to a different symmetry classes completely decouples from such a discrete state [12,17]. The coupling between the bound states and continuum band is forbidden as long as their symmetry properties are preserved, and they are classified as symmetry-protected BICs [12].…”

Section: Introductionmentioning

confidence: 99%

Metasurface Engineering through Bound States in the Continuum

et al. 2019

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Metasurfaces have attracted a lot of attention in recent years due to novel ways they provide for the efficient wavefront control and engineering of the resonant transmission. We discuss an approach allowing effectively control appearance of the sharp Fano resonances in metasurfaces associated with the bound states in the continuum. We demonstrate that by breaking the symmetry transversely, in the direction perpendicular to a metasurface with a complex unit cell, we can control the number, frequency, and type of high-Q resonances originating from bound states in the continuum. As example, we demonstrate experimentally the metasurfaces with magnetic dipole and toroidal dipole responses governed by the physics of multipolar bound states.

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Section: Introductionmentioning

confidence: 99%

Metasurface Engineering through Bound States in the Continuum

et al. 2019

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“…The physics of all-dielectric resonant nanophotonics can be broadly characterized by two major phenomena: (i) sharp spatial location of electric and magnetic fields at the nanoscale, which enhances a number of nonlinear effects, such as the harmonic generation, [6][7][8] alloptical switching, 9 and (ii) the multimodal interference via hybrid modes excitation. Many novel effects were discovered, such as directional light scattering, 10 optical magnetism, 11,12 bound states in the continuum, 13,14 toroidal and nonradiating optical anapole states, [15][16][17][18][19] etc.…”

Section: Introductionmentioning

confidence: 99%

All-dielectric metasurfaces with trapped modes: Group-theoretical description

Kupriianov

Dmitriev

et al. 2019

Journal of Applied Physics

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An all-dielectric metasurface featuring resonant conditions of the trapped mode excitation is considered. It is composed of a lattice of subwavelength particles which are made of a high-refractive-index dielectric material structured in the form of disks. Each particle within the lattice behaves as an individual dielectric resonator supporting a set of electric and magnetic (Mie-type) modes. In order to access a trapped mode (which is the TE 01δ mode of the resonator), a round eccentric penetrating hole is made in the disk. In the lattice, the disks are arranged into clusters (unit super-cells) consisting of four particles. Different orientations of holes in the super-cell correspond to different symmetry groups producing different electromagnetic response of the overall metasurface when it is irradiated by the linearly polarized waves with normal incidence. We perform a systematic analysis of the electromagnetic response of the metasurface as well as conditions of the trapped mode excitation involving the group-theoretical description, representation theory and microwave circuit theory. Both polarization-sensitive and polarization-insensitive arrangements of particles and conditions for dynamic ferromagnetic and antiferromagnetic order are derived. Finally, we observe the trapped mode manifestation in the microwave experiment.

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“…We simulate the transmission spectra for two values of , and the results are shown in Figure 4c. In the case where = 90°, and the meta-molecule is provided with C 4 -symmetry, the annihilation of the toroidal response might be attributed to the bound states in the continuum (BIC) associated with the toroidal dipole mode addressed in a recent study, [29] where a certain degree of symmetry breaking, either with regard to the excitation fields or the geometrical configurations, is required to turn BIC into quasi-BIC, in order to observe the corresponding resonances in the spectra. However, neither of them is endowed with toroidal characters.…”

Section: Quadrumer Casementioning

confidence: 99%

Toroidal Dipole Resonances in All‐Dielectric Oligomer Metasurfaces

Zhang

Lan

Gao

et al. 2019

Advcd Theory and Sims

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Dynamic toroidal multipoles have been attracting an increasing amount of attention, thanks to their unique electromagnetic properties. The concept bears great promises in the field of optical sensing as well as electromagnetic energy localization. Metal-based structures with specific designs have been widely adopted to obtain toroidal responses. However, applications for such structures are often hindered by the significant intrinsic loss when it comes to optical frequencies. Here, several configurations of all-dielectric metasurfaces, in which the meta-molecules are composed of disk oligomers (trimer, quadrumer, pentamer, and hexamer), are proposed to support toroidal dipole resonances in the near-infrared waveband when the polarization of the normally incident excitation plane wave is directed to one of the symmetry axes of the oligomers. Multipole expansion including the toroidal dipole term along with near-field electromagnetic patterns confirms the existence of strong toroidal dipolar responses within certain wavelength ranges. This work would enrich the diversity of the all-dielectric optical systems with toroidal dipole resonances.

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Toroidal dipole bound states in the continuum

Cited by 218 publications

References 67 publications

Metasurface Engineering through Bound States in the Continuum

Metasurface Engineering through Bound States in the Continuum

All-dielectric metasurfaces with trapped modes: Group-theoretical description

Toroidal Dipole Resonances in All‐Dielectric Oligomer Metasurfaces

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