Perfect Extinction of Terahertz Waves in Monolayer Graphene over 2-nm-Wide Metallic Apertures

Hyeong Ryeol Park, Seon Namgung, Xiaoshu Chen, Nathan C. Lindquist, Vincenzo Giannini, Yan Francescato, Stefan A. Maier, Sang Hyun Oh

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


High carrier mobility and tunability in graphene enable fundamental studies for plasmonics and various applications. Despite its versatility, however, single-layer graphene (SLG) suffers from poor coupling efficiency to electromagnetic waves, presenting a major challenge for photonic applications. Compared with visible or infrared radiation, terahertz (THz) waves exhibit higher absorption in SLG due to Drude-like intraband transitions, but the wavelength-to-SLG size mismatch becomes even more dramatic. Here, we experimentally demonstrate 99% extinction of THz wave transmission when SLG covers the openings of 2-nm-wide (≈λ/1 000 000) slits through a metal film. By resonantly coupling THz waves through annular nanogaps, the extremely localized fields lead to near-perfect extinction and strong absorption in SLG. Atomic-layer lithography is used to produce these nanometer-wide, millimeter-long gaps over an entire 4-in. wafer. Furthermore, by integrating these devices with an ionic liquid, enhanced intraband absorption in the SLG leads to 80% modulation of THz waves with an operational voltage as low as 1.5 V.

Original languageEnglish (US)
Pages (from-to)667-673
Number of pages7
JournalAdvanced Optical Materials
Issue number5
StatePublished - May 1 2015

Bibliographical note

Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


  • Atomic-layer lithography
  • Graphene
  • Nanogaps
  • Plasmonics
  • Terahertz nanophotonics


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