Optical vortex dichroism in chiral particles

Forbes, Kayn ORCID: https://orcid.org/0000-0002-8884-3496 and Jones, Garth (2021) Optical vortex dichroism in chiral particles. Physical Review A - Atomic, Molecular, and Optical Physics, 103. ISSN 1050-2947

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Circular dichroism is the differential rate of absorption of right- and left-handed circularly polarized light by chiral particles. Optical vortices which convey orbital angular momentum (OAM) possess a chirality associated with the clockwise or anticlockwise twisting of their wave front. Here it is highlighted that both oriented and randomly oriented chiral particles absorb photons from twisted beams at different rates depending on whether the vortex twists to the right or the left through a dipole coupling scheme. This is in contrast to previous studies that investigated dipole couplings with vortex modes in the paraxial approximation and showed no such chiral sensitivity to the vortex handedness: only in oriented media where electric quadrupole coupling contributes to optical activity effects due to absorption does such a mechanism exist for paraxial vortices. The distinct difference in the scheme highlighted in this work is that longitudinal fields are taken into account. Due to the vortex dichroism persisting in randomly oriented collections of chiral particles, the mechanism has a distinct advantage in its potential applicability in chemical and biochemical applications where the systems under study are invariably in the liquid phase. Additionally, the result is put into context in terms of the quantifiable optical chirality, highlighting that optical OAM can in fact increase the optical chirality density of an electromagnetic field.

Item Type: Article
Uncontrolled Keywords: atomic and molecular physics, and optics ,/dk/atira/pure/subjectarea/asjc/3100/3107
Faculty \ School: Faculty of Science > School of Chemistry
UEA Research Groups: Faculty of Science > Research Groups > Chemistry of Light and Energy
Faculty of Science > Research Groups > Centre for Photonics and Quantum Science
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Depositing User: LivePure Connector
Date Deposited: 03 Jun 2021 14:25
Last Modified: 09 Feb 2023 13:49
URI: https://ueaeprints.uea.ac.uk/id/eprint/80201
DOI: 10.1103/PhysRevA.103.053515


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