Permittivity-asymmetric quasi-bound states in the continuum.
Author(s)
Type
Journal Article
Abstract
Breaking the in-plane geometric symmetry of dielectric metasurfaces allows us to access a set of electromagnetic states termed symmetry-protected quasi-bound states in the continuum (qBICs). Here we demonstrate that qBICs can also be accessed by a symmetry breaking in the permittivity of the comprising materials. While the physical size of atoms imposes a limit on the lowest achievable geometrical asymmetry, weak permittivity modulations due to carrier doping, and electro-optical Pockels and Kerr effects, usually considered insignificant, open the possibility of infinitesimal permittivity asymmetries for on-demand, dynamically tunable resonances of extremely high quality factors. As a proof-of-principle, we probe the excitation of permittivity-asymmetric qBICs (ε-qBICs) using a prototype Si/TiO2 metasurface, in which the asymmetry in the unit cell is provided by the permittivity contrast of the materials. ε-qBICs are also numerically demonstrated in 1D gratings, where quality-factor enhancement and tailored interference phenomena of qBICs are shown via the interplay of geometrical and permittivity asymmetries.
Date Issued
2023-04-12
Date Acceptance
2023-03-01
Citation
Nano Letters: a journal dedicated to nanoscience and nanotechnology, 2023, 23 (7), pp.2651-2658
ISSN
1530-6984
Publisher
American Chemical Society
Start Page
2651
End Page
2658
Journal / Book Title
Nano Letters: a journal dedicated to nanoscience and nanotechnology
Volume
23
Issue
7
Copyright Statement
Copyright © 2023 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in [JournalTitle], after peer review and technical editing by the publisher. To access the final edited and published work see [insert hyperlinked DOI, see ACS Articles on Request https://pubs.acs.org/page/4authors/benefits/index.html#articles-request]
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/36946720
Subjects
emergence
metasurface
permittivity
quasi-BIC
symmetry breaking
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2023-03-22