Habib Ammari, Bryn Davies, Erik Orvehed Hiltunen, Hyundae Lee, Sanghyeon Yu

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


When sources of energy gain and loss are introduced to a wave scattering system, the underlying mathematical formulation will be non-Hermitian. This paves the way for the existence of exceptional points, where eigenmodes are linearly dependent. The primary goal of this work is to study the existence of exceptional points in high-contrast subwavelength metamaterials. We begin by studying a parity–time-symmetric pair of subwavelength resonators and prove that this system supports asymptotic exceptional points. These are points at which the subwavelength eigenvalues and eigenvectors coincide at leading order in the asymptotic parameter. We then investigate the exotic scattering behavior of a metascreen composed of repeating parity–time-symmetric pairs of subwavelength resonators. We prove that the non-Hermitian nature of this structure means that it exhibits asymptotic unidirectional reflectionless transmission at certain frequencies and demonstrate extraordinary transmission close to these frequencies.

Original languageEnglish
Pages (from-to)6223-6253
Number of pages31
JournalSIAM Journal on Mathematical Analysis
Issue number6
Publication statusPublished - 2022 Dec

Bibliographical note

Publisher Copyright:
© 2022 Society for Industrial and Applied Mathematics.


  • PT symmetry
  • exceptional points
  • extraordinary transmission
  • metamaterials
  • subwavelength resonance
  • unidirectional reflection

ASJC Scopus subject areas

  • Analysis
  • Computational Mathematics
  • Applied Mathematics


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