Control of Quasibound Waves in Spiral Metasurfaces

Sang Yeon Cho, Jason Sun, Adam C. Overvig, Andrea Alù, Weimin Zhou

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Resonant light scattering by a subwavelength dielectric resonator array can show narrow, highly tunable resonant lineshapes from the interaction among multiple resonances. Several approaches have been introduced to control the spectral response of resonant light scattering, including optimization of the aspect ratio of cylindrical resonators, breaking in-plane inverse symmetry of coupled resonators, and operating periodic structures at the Î" point in reciprocal space. In this paper, we report the experimental demonstration of the control of resonant light scattering by subwavelength spiral resonator arrays. The fabricated metasurfaces support two types of resonances: The first one characterized by a Lorentzian peak with a long lifetime and the second type with a short lifetime supported by the lattice. By controlling the coupling strength between these two resonances through tailored broken symmetries, the resonant line shape of the spiral metasurface can be precisely tuned. The measured spectra show an ultrawide frequency tuning (over 16 THz) of the resonant mode by changing the spiral parameter at a fixed lattice constant. A temporal couple-mode theory combined with frequency-domain finite element method simulations was used to describe the measured transmission spectra of the fabricated metasurfaces.

Original languageEnglish
Pages (from-to)3592-3599
Number of pages8
JournalACS Photonics
Volume9
Issue number11
DOIs
StatePublished - 16 Nov 2022

Keywords

  • Fano resonances
  • bound states in the continuum
  • metasurfaces
  • spiral resonators
  • temporal couple mode theory

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