Controlled Fano resonances via symmetry breaking in metamaterials for high-sensitive infrared spectroscopy

Shuhei Hara, Atsushi Ishikawa, Takuo Tanaka, Yasuhiko Hayashi, Kenji Tsuruta

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A high-sensitive polarized surface-enhanced infrared absorption (polarized SEIRA) is proposed and demonstrated by utilizing the resonant coupling of Fano-resonant mode of the asymmetric metamaterials and IR vibrational mode of a polymer nano-film. The asymmetric metamaterials consisting of an Au nano-rod pair with a coupling nano-antenna were fabricated and characterized to demonstrate the controlled Fano resonances at 1730 cm-1, which spectrally overlapped with the C=O stretching vibrational mode. In the co-polarized SEIRA measurement, the C=O mode of the PMMA nano-film was clearly observed as a conventional anti-resonant peak within the Fano line-shape of the metamaterial. For the cross-polarized case, on the other hand, a distinctive dip appeared within a cross-polarized transmission peak of the metamaterial. Since the unwanted background is strongly suppressed in the cross-polarized detection scheme, the signal contrast was dramatically improved, allowing for the attomole detection of the C=O bond in the far-field measurement. Our metamaterial approach achieves the significant improvement of signal-to-background ratio in the far-field measurement, thus paving the way toward the high-sensitive analysis of functional group in direct IR spectroscopy.

Original languageEnglish
Title of host publicationMetamaterials, Metadevices, and Metasystems 2016
ISBN (Electronic)9781510602274
Publication statusPublished - 2016
EventMetamaterials, Metadevices, and Metasystems 2016 - San Diego, United States
Duration: Aug 28 2016Sep 1 2016


OtherMetamaterials, Metadevices, and Metasystems 2016
Country/TerritoryUnited States
CitySan Diego


  • Fano resonances
  • Plasmonic metamaterials
  • Plasmonic sensors
  • Symmetry breaking

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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