Roles of superchirality and interference in chiral plasmonic biodetection

Gilroy, C., Hashiyada, S., Endo, K., Karimullah, A. S. , Barron, L., Okamoto, H., Togawa, Y. and Kadodwala, M. (2019) Roles of superchirality and interference in chiral plasmonic biodetection. Journal of Physical Chemistry C, 123(24), pp. 15195-15203. (doi: 10.1021/acs.jpcc.9b02791)

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Abstract

Chiral plasmonic nanostructures enable ≤pg detection and characterization of biomaterials. The sensing capabilities are associated with the chiral asymmetry of the near fields, which locally can be greater than equivalent circularly polarized light, a property referred to as superchirality. However, sensing abilities do not simply scale with the magnitude of superchirality. We show that chiral molecular sensing is correlated to the thickness of a nanostructure. This observation is reconciled with a previously unconsidered interference mechanism for the sensing phenomenon. It involves the “dissipation” of optical chirality into chiral material currents through the interference of fields generated by two spatially separated chiral modes. The presence of a chiral dielectric causes an asymmetric change in the phase difference, resulting in asymmetric changes to chiroptical properties. Thus, designing a chiral plasmonic sensor requires engineering a substrate that can sustain both superchiral fields and an interference effect.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kadodwala, Professor Malcolm and Togawa, Dr Yoshihiko and Karimullah, Dr Affar and Barron, Professor Laurence and Gilroy, Mr Cameron
Authors: Gilroy, C., Hashiyada, S., Endo, K., Karimullah, A. S., Barron, L., Okamoto, H., Togawa, Y., and Kadodwala, M.
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:1932-7447
ISSN (Online):1932-7455
Published Online:28 May 2019
Copyright Holders:Copyright © 2019 American Chemical Society
First Published:First published in Journal of Physical Chemistry C 123(24):15195-15203
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
683531Consortium for advanced materials based on spin chiralityRobert StampsEngineering and Physical Sciences Research Council (EPSRC)EP/M024423/1S&E P&A - PHYSICS & ASTRONOMY
636381EPSRC Centre for Doctoral Training in Sensing and MeasurementAndrew HarveyEngineering and Physical Sciences Research Council (EPSRC)EP/L016753/1S&E P&A - PHYSICS & ASTRONOMY