Directional Plasmonic Excitation by Helical Nanotips

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one...

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Bibliographic Details
Main Authors: Leeju Singh, Nicolò Maccaferri, Denis Garoli, Yuri Gorodetski
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Nanomaterials
Subjects:
Online Access:https://www.mdpi.com/2079-4991/11/5/1333
Description
Summary:The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one, such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light–plasmon coupling and to achieve a directional plasmonic excitation. Here, we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of the nanostructure.
ISSN:2079-4991