Far field detection of terahertz near field enhancement of sub-wavelength slits using Kirchhoff integral formalism

J. S. Kyoung, M. A. Seo, H. R. Park, K. J. Ahn, D. S. Kim

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Abstract

We demonstrate that the near field enhancement of sub-wavelength slits can be experimentally determined in the far field by using a reference aperture. Our simple model derived from the Kirchhoff integral formalism shows that enhancement of the near field at a slit exit with respect to the incident wave can be read in the transmitted amplitude through the slit attached on a reference aperture, normalized by the transmitted amplitude through the reference aperture. Furthermore, the near field enhancement obtained in such a way is essentially independent of the reference aperture size. By performing terahertz time domain spectroscopy we experimentally confirm the inverse frequency dependence of the near field enhancement of extremely narrow slits and measure the maximum field enhancement reaching 200 at 0.1 THz for a 500-nm-width slit.

Original languageEnglish (US)
Pages (from-to)4907-4910
Number of pages4
JournalOptics Communications
Volume283
Issue number24
DOIs
StatePublished - Dec 15 2010

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Keywords

  • Field enhancement
  • Kirchhoff integral
  • Terahertz

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