On the conservation of helicity in a chiral medium

Crimin, F. , Mackinnon, N., Götte, J. B. and Barnett, S. (2019) On the conservation of helicity in a chiral medium. Journal of Optics, 21(9), 094003. (doi: 10.1088/2040-8986/ab387c)

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Abstract

We consider the energy and helicity densities of circularly polarised light within a lossless chiral medium, characterised by the chirality parameter β. A form for the helicity density is introduced, valid to first order in β, that produces a helicity of ±\hbar per photon for right and left circular polarisation, respectively. This is in contrast to the result obtained if we use the form of the helicity density employed for linear media. We examine the helicity continuity equation, and show that this modified form of the helicity density is required for consistency with the dual symmetry condition of a chiral medium with a constant value of ε/μ. Extending the results to arbitrary order in β establishes an exact relationship between the energy and helicity densities in a chiral medium.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:MacKinnon, Mr Neel and Crimin, Dr Frances and Goette, Dr Joerg and Barnett, Professor Stephen
Authors: Crimin, F., Mackinnon, N., Götte, J. B., and Barnett, S.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Journal of Optics
Publisher:IOP Publishing
ISSN:2040-8978
ISSN (Online):2040-8986
Published Online:05 August 2019
Copyright Holders:Copyright © 2019 IOP Publishing Ltd
First Published:First published in Journal of Optics 21:094003
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
3015920Foundations and Applications of Optical Forces - Enhancement awardStephen BarnettThe Royal Society (ROYSOC)RP\EA\180010P&S - Physics & Astronomy
721291Astronomy and physics, theoretical physics and application physics / Quantum Theory. Royal Society Research Professorship.Stephen BarnettThe Royal Society (ROYSOC)RP150122S&E P&A - PHYSICS & ASTRONOMY
738201EPSRC DTP 16/17 and 17/18Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/N509668/1R&I - RESEARCH STRATEGY & INNOVATION