Extreme Nonreciprocity in Metasurfaces Based on Bound States in the Continuum

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date

2024-01-04

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Department of Electronics and Nanoengineering

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Mcode

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en

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Advanced Optical Materials, Volume 12, issue 1

Abstract

Nonreciprocal devices, including optical isolators, phase shifters, and amplifiers, are pivotal for advanced optical systems. However, exploiting natural materials is challenging due to their weak magneto-optical (MO) effects, requiring substantial thickness to construct effective optical devices. In this study, it is demonstrated that subwavelength metasurfaces supporting bound states in the continuum (BICs) and made of conventional ferrimagnetic material can exhibit strong nonreciprocity in the Faraday configuration and near-unity magnetic circular dichroism (MCD). These metasurfaces enhance the MO effect by 3–4 orders of magnitude compared to a continuous film of the same material. This significant enhancement is achieved by leveraging Huygens' condition in the metasurface whose structural units support paired electric and magnetic dipole resonances. The multi-mode temporal coupled mode theory (CMT) is developed for the observed enhancement of the MO effect, and the findings with the full-wave simulations are confirmed.

Description

Funding Information: This research was supported by the Beatriz Galindo excellence grant (grant No. BG‐00024), the Spanish National Research Council (grant No. PID2021‐128442NA‐I00), and the Academy of Finland (Project No. 356797). Publisher Copyright: © 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH.

Keywords

bound states in the continuum, Faraday rotation, magneto-optical effect, metasurfaces

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DOI

10.1002/adom.202301455

Citation

Máñez-Espina, L M, Faniayeu, I, Asadchy, V & Díaz-Rubio, A 2024, 'Extreme Nonreciprocity in Metasurfaces Based on Bound States in the Continuum', Advanced Optical Materials, vol. 12, no. 1, 2301455. https://doi.org/10.1002/adom.202301455

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https://urn.fi/URN:NBN:fi:aalto-202401312199

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