Graphene-Tuned, Tightly Coupled Hybrid Plasmonic Meta-Atoms

Kai Chen, Ke Li, Yiming Wang, Zihao Zhang, Yanpeng Shi, Aimin Song, Yifei Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

Tightly coupled meta-atoms (TCMAs) are densely packed metamaterials with unnatural refractive indexes. Actively modulated TCMAs with tunable optical properties have found many applications in beam shaping, holography, and enhanced light–matter interactions. Typically, TCMAs are studied in the classic Bloch theory. Here, tightly coupled H-shaped meta-atoms are proposed with an ultra-high permittivity of ~6000, and their active modulation with graphene is designed by using the tightly coupled dipole array (TCDA) theory. The H-shaped meta-atoms are used as dipole arms, and the graphene strips function as the dipole loads. By tuning the chemical potential of graphene, the resonant amplitude, frequency, and permittivity are dynamically modulated. The simulations indicate that the real and imaginary parts of permittivity change from 6854 to 1522 and from 7356 to 2870, respectively. The experimental validation demonstrates a modulation depth of 11.6% in the resonant frequency, i.e., from 219.4 to 195 GHz, and a substantial 52.5% modulation depth in transmittance under a bias voltage of less than 1.5 V.

Original languageEnglish
Article number713
JournalNanomaterials
Volume14
Issue number8
DOIs
Publication statusPublished - Apr 2024

Keywords

  • graphene
  • plasmonic
  • terahertz
  • tightly coupled antenna array
  • tightly coupled meta-atom

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