Toroidal dipole excitations in metamolecules formed by interacting plasmonic nanorods
Toroidal dipole excitations in metamolecules formed by interacting plasmonic nanorods
We show how the elusive toroidal dipole moment appears as a radiative excitation eigenmode in a metamolecule resonator that is formed by pairs of plasmonic nanorods. We analyze one such nanorod configuration-a toroidal metamolecule. We find that the radiative interactions in the toroidal metamolecule can be qualitatively represented by a theoretical model based on an electric point dipole arrangement. Both a finite-size rod model and the point dipole approximation demonstrate how the toroidal dipole moment is subradiant and difficult to excite by incident light. By means of breaking the geometric symmetry of the metamolecule, the toroidal mode can be excited by linearly polarized light and appears as a Fano resonance dip in the forward scattered light. We provide simple optimization protocols for maximizing the toroidal dipole mode excitation. This opens up possibilities for simplified control and driving of metamaterial arrays consisting of toroidal dipole unit-cell resonators.
1-12
Watson, Derek W.
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Jenkins, Stewart D.
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Ruostekoski, Janne
2beb155e-64b0-4ee9-9cfe-079947a9c9f4
Fedotov, Vassili A.
3725f5cc-2d0b-4e61-95c5-26d187c84f25
Zheludev, Nikolay I.
32fb6af7-97e4-4d11-bca6-805745e40cc6
16 March 2016
Watson, Derek W.
4cb78431-9921-4c6e-9d68-0e8eaa3628e5
Jenkins, Stewart D.
65d861fb-b85a-4927-805a-7c906fca26c6
Ruostekoski, Janne
2beb155e-64b0-4ee9-9cfe-079947a9c9f4
Fedotov, Vassili A.
3725f5cc-2d0b-4e61-95c5-26d187c84f25
Zheludev, Nikolay I.
32fb6af7-97e4-4d11-bca6-805745e40cc6
Watson, Derek W., Jenkins, Stewart D., Ruostekoski, Janne, Fedotov, Vassili A. and Zheludev, Nikolay I.
(2016)
Toroidal dipole excitations in metamolecules formed by interacting plasmonic nanorods.
Physical Review B, 93 (125420), .
(doi:10.1103/PhysRevB.93.125420).
Abstract
We show how the elusive toroidal dipole moment appears as a radiative excitation eigenmode in a metamolecule resonator that is formed by pairs of plasmonic nanorods. We analyze one such nanorod configuration-a toroidal metamolecule. We find that the radiative interactions in the toroidal metamolecule can be qualitatively represented by a theoretical model based on an electric point dipole arrangement. Both a finite-size rod model and the point dipole approximation demonstrate how the toroidal dipole moment is subradiant and difficult to excite by incident light. By means of breaking the geometric symmetry of the metamolecule, the toroidal mode can be excited by linearly polarized light and appears as a Fano resonance dip in the forward scattered light. We provide simple optimization protocols for maximizing the toroidal dipole mode excitation. This opens up possibilities for simplified control and driving of metamaterial arrays consisting of toroidal dipole unit-cell resonators.
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PhysRevB.93.pdf
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More information
Accepted/In Press date: 3 February 2016
e-pub ahead of print date: 16 March 2016
Published date: 16 March 2016
Organisations:
Optoelectronics Research Centre, Mathematical Sciences, Applied Mathematics
Identifiers
Local EPrints ID: 390261
URI: http://eprints.soton.ac.uk/id/eprint/390261
ISSN: 1550-235X
PURE UUID: 48cae4b3-3278-4517-ad96-99a75b35122e
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Date deposited: 22 Mar 2016 14:01
Last modified: 15 Mar 2024 02:45
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Contributors
Author:
Derek W. Watson
Author:
Stewart D. Jenkins
Author:
Vassili A. Fedotov
Author:
Nikolay I. Zheludev
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