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Near- and Far-Field Excitation of Topological Plasmonic Metasurfaces
Article

Topological-Insulator-Based Gap-Surface Plasmon Metasurfaces

1
Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539 München, Germany
2
Department of Physics, Imperial College London, London SW7 2AZ, UK
3
MQ Photonics Research Centre, Department of Physics and Astronomy, Macquarie University, Macquarie Park, NSW 2109, Australia
*
Author to whom correspondence should be addressed.
Photonics 2021, 8(2), 40; https://doi.org/10.3390/photonics8020040
Received: 30 December 2020 / Revised: 29 January 2021 / Accepted: 1 February 2021 / Published: 4 February 2021
(This article belongs to the Special Issue Plasmonic Metasurfaces)
Topological insulators (TIs) have unique highly conducting symmetry-protected surface states while the bulk is insulating, making them attractive for various applications in condensed matter physics. Recently, topological insulator materials have been tentatively applied for both near- and far-field wavefront manipulation of electromagnetic waves, yielding superior plasmonic properties in the ultraviolet (UV)-to-visible wavelength range. However, previous reports have only demonstrated inefficient wavefront control based on binary metasurfaces that were digitalized on a TI thin film or non-directional surface plasmon polariton (SPP) excitation. Here, we numerically demonstrated the plasmonic capabilities of the TI Bi2Te3 as a material for gap–surface plasmon (GSP) metasurfaces. By employing the principle of the geometric phase, a far-field beam-steering metasurface was designed for the visible spectrum, yielding a cross-polarization efficiency of 34% at 500 nm while suppressing the co-polarization to 0.08%. Furthermore, a birefringent GSP metasurface design was studied and found to be capable of directionally exciting SPPs depending on the incident polarization. Our work forms the basis for accurately controlling the far- and near-field responses of TI-based GSP metasurfaces in the visible spectral range. View Full-Text
Keywords: topological insulator; gap–surface plasmon metasurface; Bi2Te3; MIM metasurface; beam steering; SPP excitation topological insulator; gap–surface plasmon metasurface; Bi2Te3; MIM metasurface; beam steering; SPP excitation
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MDPI and ACS Style

Aigner, A.; Maier, S.A.; Ren, H. Topological-Insulator-Based Gap-Surface Plasmon Metasurfaces. Photonics 2021, 8, 40. https://doi.org/10.3390/photonics8020040

AMA Style

Aigner A, Maier SA, Ren H. Topological-Insulator-Based Gap-Surface Plasmon Metasurfaces. Photonics. 2021; 8(2):40. https://doi.org/10.3390/photonics8020040

Chicago/Turabian Style

Aigner, Andreas, Stefan A. Maier, and Haoran Ren. 2021. "Topological-Insulator-Based Gap-Surface Plasmon Metasurfaces" Photonics 8, no. 2: 40. https://doi.org/10.3390/photonics8020040

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