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Point-dipole approximation for small systems of strongly coupled radiating nanorods

Systems of closely-spaced resonators can be strongly coupled by interactions mediated by scattered electromagnetic fields. In large systems the resulting response has been shown to be more sensitive to these collective interactions than to the detailed structure of individual resonators. Attempts to...

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Autores principales: Watson, Derek W., Jenkins, Stewart D., Fedotov, Vassili A., Ruostekoski, Janne
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450961/
https://www.ncbi.nlm.nih.gov/pubmed/30952960
http://dx.doi.org/10.1038/s41598-019-41327-6
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author Watson, Derek W.
Jenkins, Stewart D.
Fedotov, Vassili A.
Ruostekoski, Janne
author_facet Watson, Derek W.
Jenkins, Stewart D.
Fedotov, Vassili A.
Ruostekoski, Janne
author_sort Watson, Derek W.
collection PubMed
description Systems of closely-spaced resonators can be strongly coupled by interactions mediated by scattered electromagnetic fields. In large systems the resulting response has been shown to be more sensitive to these collective interactions than to the detailed structure of individual resonators. Attempts to describe such systems have resulted in point-dipole approximations to resonators that are computationally efficient for large resonator ensembles. Here we provide a detailed study for the validity of point dipole approximations in small systems of strongly coupled plasmonic nanorods, including the cases of both super-radiant and subradiant excitations, where the characteristics of the excitation depends on the spatial separation between the nanorods. We show that over an appreciable range of rod lengths centered on 210 nm, when the relative separation kl in terms of the resonance wave number of light k satisfies [Formula: see text] , the point electric dipole model becomes accurate. However, when the resonators are closer, the finite-size and geometry of the resonators modifies the excitation modes, in particular the cooperative mode line shifts of the point dipole approximation begin to rapidly diverge at small separations. We also construct simplified effective models by describing a pair of nanorods as a single effective metamolecule.
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spelling pubmed-64509612019-04-11 Point-dipole approximation for small systems of strongly coupled radiating nanorods Watson, Derek W. Jenkins, Stewart D. Fedotov, Vassili A. Ruostekoski, Janne Sci Rep Article Systems of closely-spaced resonators can be strongly coupled by interactions mediated by scattered electromagnetic fields. In large systems the resulting response has been shown to be more sensitive to these collective interactions than to the detailed structure of individual resonators. Attempts to describe such systems have resulted in point-dipole approximations to resonators that are computationally efficient for large resonator ensembles. Here we provide a detailed study for the validity of point dipole approximations in small systems of strongly coupled plasmonic nanorods, including the cases of both super-radiant and subradiant excitations, where the characteristics of the excitation depends on the spatial separation between the nanorods. We show that over an appreciable range of rod lengths centered on 210 nm, when the relative separation kl in terms of the resonance wave number of light k satisfies [Formula: see text] , the point electric dipole model becomes accurate. However, when the resonators are closer, the finite-size and geometry of the resonators modifies the excitation modes, in particular the cooperative mode line shifts of the point dipole approximation begin to rapidly diverge at small separations. We also construct simplified effective models by describing a pair of nanorods as a single effective metamolecule. Nature Publishing Group UK 2019-04-05 /pmc/articles/PMC6450961/ /pubmed/30952960 http://dx.doi.org/10.1038/s41598-019-41327-6 Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Watson, Derek W.
Jenkins, Stewart D.
Fedotov, Vassili A.
Ruostekoski, Janne
Point-dipole approximation for small systems of strongly coupled radiating nanorods
title Point-dipole approximation for small systems of strongly coupled radiating nanorods
title_full Point-dipole approximation for small systems of strongly coupled radiating nanorods
title_fullStr Point-dipole approximation for small systems of strongly coupled radiating nanorods
title_full_unstemmed Point-dipole approximation for small systems of strongly coupled radiating nanorods
title_short Point-dipole approximation for small systems of strongly coupled radiating nanorods
title_sort point-dipole approximation for small systems of strongly coupled radiating nanorods
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450961/
https://www.ncbi.nlm.nih.gov/pubmed/30952960
http://dx.doi.org/10.1038/s41598-019-41327-6
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