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A tunable electromagnetic metagrating

Title: A tunable electromagnetic metagrating
Authors: Putley, HJ
Guenneau, S
Porter, R
Craster, RV
Item Type: Journal Article
Abstract: We explore electromagnetic (EM) wave incidence upon gratings of reconfigurable metamaterial cylinders, which collectively act as a metagrating, to identify their potential as reconfigurable subwavelength surfaces. The metacylinders are created by a closely spaced, microstructured array of thin plates that, in the limit of small inter-plate spacing, are described by a semi-analytical continuum model. We build upon metacylinder analysis in water waves, translating this to EM for TE polarization (longitudinal magnetic field) for which the metacylinders exhibit anisotropic scattering; this is exploited for the multiple scattering of light by an infinite metagrating of uniform cylinder radius and angle, for which we retrieve the far-field reflection and transmission spectra for plane-wave incidence. These spectra reveal unusual effects including perfect reflection and a negative Goos–Hänchen shift in the transmitted field, as well as perfect symmetry in the far-field scattering coefficients. The metagrating also hosts Rayleigh–Bloch surface waves, whose dispersion is contingent on the uniform cylinder angle, shifting under rotation towards the light-line as the cylinder angle approaches the horizontal. For both plane-wave scattering and the calculation of the array-guided modes, the cylinder angle is the principal variable in determining the wave interaction, and the metagrating is tunable simply through rotation of the constituent metacylinders.
Issue Date: Dec-2022
Date of Acceptance: 17-Nov-2022
URI: http://hdl.handle.net/10044/1/105960
DOI: 10.1098/rspa.2022.0454
ISSN: 1364-5021
Publisher: The Royal Society
Start Page: 1
End Page: 22
Journal / Book Title: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume: 478
Issue: 2268
Copyright Statement: © 2022 The Author(s) Published by the Royal Society. All rights reserved.
Publication Status: Published
Open Access location: https://research-information.bris.ac.uk/ws/portalfiles/portal/350479989/Metacylinder_EM_RSPA_submission_Edited.pdf
Online Publication Date: 2022-12-14
Appears in Collections:Condensed Matter Theory
Physics
Faculty of Natural Sciences