Tuning dipolar and multipolar resonances of chiral silicon nanostructures for control of near field superchirality

Koyroytsaltis-McQuire, D. J.P., Kumar, R., Javorfi, T., Siligardi, G., Gadegaard, N. and Kadodwala, M. (2024) Tuning dipolar and multipolar resonances of chiral silicon nanostructures for control of near field superchirality. Nanoscale, 16, pp. 110-122. (doi: 10.1039/d3nr05285k) (PMID:38063462)

Abstract

Chiral materials display a property called optical activity, which is the capability to interact differentially with left and right circularly polarised light. This leads to the ability to manipulate the polarisation state of light, which has a broad range of applications spanning from energy efficient displays to quantum technologies. Both synthesised and engineered chiral nanomaterials are exploited in such devices. The design strategy for optimising the optical activity of a chiral material is typically based on maximising a single parameter, the electric dipole–magnetic dipole response. Here we demonstrate an alternative approach of controlling optical activity by manipulating both the dipole and multipolar response of a nanomaterial. This provides an additional parameter for material design, affording greater flexibility. The exemplar systems used to illustrate the strategy are nanofabricated chiral silicon structures. The multipolar response of the structures, and hence their optical activity, can be controlled simply by varying their height. This phenomenon allows optical activity and the creation of so called superchiral fields, with enhanced asymmetries, to be controlled over a broader wavelength range, than is achievable with just the electric dipole–magnetic dipole response. This work adds to the material design toolbox providing a route to novel nanomaterials for optoelectronics and sensing applications.

• Item Type: Articles
• Additional Information: The authors acknowledge financial support from the Engineering and Physical Sciences Research Council (EP/ P00086X/1 and EP/M024423/1). Technical support from the James Watt Nanofabrication Centre (JWNC) and Diamond Light Source Ltd is acknowledged. DKM was awarded a studentship by the EPSRC. M.K. acknowledges the Leverhulme Trust for the award of a Research Fellowship.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gadegaard, Professor Nikolaj and Kadodwala, Professor Malcolm and Koyroytsaltis-McQuire, Dominic
• Authors: Koyroytsaltis-McQuire, D. J.P., Kumar, R., Javorfi, T., Siligardi, G., Gadegaard, N., and Kadodwala, M.
• College/School: College of Science and Engineering > School of Chemistry; College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: Nanoscale
• Publisher: Royal Society of Chemistry
• ISSN: 2040-3364
• ISSN (Online): 2040-3372
• Published Online: 05 December 2023
• Copyright Holders: Copyright © The Royal Society of Chemistry2024
• First Published: First published in Nanoscale 16:110-122
• Publisher Policy: Reproduced under a creative commons licence