Topological control of chirality and spin with structured light

Mkhumbuza, Light, Ornelas, Pedro, Dudley, Angela, Nape, Isaac and Forbes, Kayn A. ORCID: https://orcid.org/0000-0002-8884-3496 (2026) Topological control of chirality and spin with structured light. Light: Science and Applications, 15 (1). ISSN 2047-7538

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Abstract

Structured light beams with engineered topological properties offer a powerful means to control spin angular momentum (SAM) and optical chirality, key quantities shaped by spin-orbit interaction (SOI) in light. Such effects are commonly associated with non-paraxial focusing or light-matter interfaces. Here, we demonstrate that higher-order Poincaré modes carrying a tunable Pancharatnam topological charge ℓ p enable deterministic control of SOI entirely in free space and within the paraxial regime. We show that modulation of ℓ p drives a measurable radial separation of circular polarization components - a free-space optical Hall effect arising from propagation-induced mechanisms alone. The effect originates from differential Gouy-phase evolution and radial divergence between the two circular components of an initially spin-balanced vector beam. This identifies ℓ p as a single, tunable parameter linking Pancharatnam topology to paraxial spin-orbit coupling, establishing a simple and material-independent route to generate and control optical chirality and SAM. This approach provides new opportunities for tunable optical manipulation, chiral sensing, and high-dimensional photonic information processing. (Figure presented.)

Item Type: Article
Additional Information: Data availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.
Faculty \ School: Faculty of Science > School of Chemistry, Pharmacy and Pharmacology
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Depositing User: LivePure Connector
Date Deposited: 01 May 2026 10:02
Last Modified: 18 Jun 2026 20:58
URI: https://ueaeprints.uea.ac.uk/id/eprint/102870
DOI: 10.1038/s41377-026-02278-6

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