Optical Anapole Metamaterial

P.C. Wu, C.Y. Liao, V. Savinov, T.L. Chung, W.T. Chen, Y.-W. Huang, P.R. Wu, Y.-H. Chen, A.-Q. Liu, N.I. Zheludev, Din-ping Tsai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

184 Citations (Scopus)


© 2018 American Chemical Society.The toroidal dipole is a localized electromagnetic excitation independent from the familiar magnetic and electric dipoles. It corresponds to currents flowing along minor loops of a torus. Interference of radiating induced toroidal and electric dipoles leads to anapole, a nonradiating charge-current configuration. Interactions of induced toroidal dipoles with electromagnetic waves have recently been observed in artificial media at microwave, terahertz, and optical frequencies. Here, we demonstrate a quasi-planar plasmonic metamaterial, a combination of dumbbell aperture and vertical split-ring resonator, that exhibits transverse toroidal moment and resonant anapole behavior in the optical part of the spectrum upon excitation with a normally incident electromagnetic wave. Our results prove experimentally that toroidal modes and anapole modes can provide distinct and physically significant contributions to the absorption and dispersion of slabs of matter in the optical part of the spectrum in conventional transmission and reflection experiments.
Original languageEnglish
Pages (from-to)1920-1927
Number of pages8
JournalACS Nano
Issue number2
Publication statusPublished - 27 Feb 2018
Externally publishedYes


  • anapole mode
  • magnetic dipole
  • plasmonic metamaterial
  • split-ring resonator
  • toroidal dipole

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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