Symmetry reduction and shape effects in concave chiral plasmonic structures

Paterson, G. W. , Karimullah, A. S. , Smith, S. G., Kadodwala, M. and MacLaren, D. A. (2018) Symmetry reduction and shape effects in concave chiral plasmonic structures. Journal of Physical Chemistry C, 122(9), pp. 5049-5056. (doi: 10.1021/acs.jpcc.7b12260)

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Chiral metamaterials have shown a number of interesting properties which result from the interaction of the chiral near-field they produce with light and matter. We investigate the influence of structural imperfections on the plasmonic properties of a chiral gold “gammadion”, using electron energy loss spectroscopy to directly inform simulations of realistic, imperfect structures. Unlike structures of simple convex geometry, the lowest energy modes of the ideal concave gammadion have a quadrupole and dipole character, with the mode energies determined by the nature of electrostatic coupling between the gammadion arms. These modes are strongly affected by structural imperfections that are inherent to the material properties and lithographic patterning. Even subwavelength-scale imperfections reduce the symmetry, lift mode degeneracies convert dark modes into bright ones and significantly alter the mode energy, its near-field strength, and chirality. Such effects will be common to a number of multitipped concave structures currently being investigated for the chiral fields they support.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Karimullah, Dr Affar and Kadodwala, Professor Malcolm and MacLaren, Professor Donald and Smith, Mr Scott and Paterson, Dr Gary
Authors: Paterson, G. W., Karimullah, A. S., Smith, S. G., Kadodwala, M., and MacLaren, D. A.
College/School:College of Science and Engineering > School of Chemistry
College of Science and Engineering > School of Physics and Astronomy
Journal Name:Journal of Physical Chemistry C
Publisher:American Chemical Society
ISSN (Online):1932-7455
Published Online:05 February 2018
Copyright Holders:Copyright © 2018 American Chemical Society
First Published:First published in Journal of Physical Chemistry C 122(9): 5049-5056
Publisher Policy:Reproduced in accordance with the publisher copyright policy
Data DOI:10.5525/gla.researchdata.581

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
631041New directions in materials characterisation using vortex electron microscopy and spectroscopyDonald MaclarenEngineering and Physical Sciences Research Council (EPSRC)EP/L001969/1S&E P&A - PHYSICS & ASTRONOMY
683531Consortium for advanced materials based on spin chiralityRobert StampsEngineering and Physical Sciences Research Council (EPSRC)EP/M024423/1S&E P&A - PHYSICS & ASTRONOMY