On the orbit-induced spin density of tightly focused optical vortex beams: ellipticity and helicity

Forbes, Kayn ORCID: https://orcid.org/0000-0002-8884-3496 (2024) On the orbit-induced spin density of tightly focused optical vortex beams: ellipticity and helicity. Journal of Optics, 26 (8). ISSN 2040-8978

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Abstract

It has recently been established that a linearly-polarized optical vortex possesses spin angular momentum density in the direction of propagation (longitudinal spin) under tight-focusing. The helicity of light has long been associated with longitudinal spin angular momentum. Here we show that the longitudinal spin density of linearly-polarized vortices is anomalous because it has no associated helicity. It was also recently determined that the polarization-independent helicity of tightly-focused optical vortices is associated with their transverse spin momentum density. The key finding of this work is the fact that, in general, longitudinal spin can not necessarily be associated with helicity, and transverse spin is in general not associated with a zero helicity, and such extraordinary behaviour manifests most clearly for optical vortices under non-paraxial conditions.

Item Type:	Article
Uncontrolled Keywords:	chirality,helicity,nano-optics,optical vortices,spin angular momentum,electronic, optical and magnetic materials,atomic and molecular physics, and optics ,/dk/atira/pure/subjectarea/asjc/2500/2504
Faculty \ School:	Faculty of Science > School of Chemistry (former - to 2024)
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	23 Jul 2024 11:33
Last Modified:	20 Dec 2024 01:11
URI:	https://ueaeprints.uea.ac.uk/id/eprint/96008
DOI:	10.1088/2040-8986/ad5f40

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