Degenerate critical coupling in all-dielectric metasurface absorbers.

Published

Journal Article

We develop the theory of all-dielectric absorbers based on temporal coupled mode theory (TCMT), with parameters extracted from eigenfrequency simulations. An infinite square array of cylindrical resonators embedded in air is investigated, and we find that it supports two eigenmodes of opposite symmetry that are each responsible for half of the total absorption. The even and odd eigenmodes are found to be the hybrid electric (EH111) and hybrid magnetic (HE111) waveguide modes of a dielectric wire of circular cross section, respectively. The geometry of the cylindrical array is shown to be useful for individual tuning of the radiative loss rates of the eigenmodes, thus permitting frequency degeneracy. Further, by specifying the resonators' loss tangent, the material loss rate can be made to equal the radiative loss rate, thus achieving a state of degenerate critical coupling and perfect absorption. Our results are supported by S-parameter simulations, and agree well with waveguide theory.

Full Text

Duke Authors

Cited Authors

  • Ming, X; Liu, X; Sun, L; Padilla, WJ

Published Date

  • October 2017

Published In

Volume / Issue

  • 25 / 20

Start / End Page

  • 24658 - 24669

PubMed ID

  • 29041411

Pubmed Central ID

  • 29041411

Electronic International Standard Serial Number (EISSN)

  • 1094-4087

International Standard Serial Number (ISSN)

  • 1094-4087

Digital Object Identifier (DOI)

  • 10.1364/oe.25.024658

Language

  • eng