Enhanced transmission through nano-aperture on a tapered metallic substrate

C. M. Wang, B. Ung, Y. Sheng, J. Y. Chang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The optical transmission and distribution through a subwavelength slit on a tapered metallic substrate was investigated. By using a 45° tapered structure rather than a traditional metallic plate, a 6-fold transmission enhancement could be achieved. This is due to the asymmetrical excitation of surface waves and the matching of propagation constants between the surface waves and slit waveguide. In addition, by patterning surface corrugations in the exit plane, the beam could be focused. By tuning the period of the surface corrugations, we were able to adjust the focal length. For an input wavelength of 0.5 μm, the focal point could be kept within 0.6 μm with a focal length extending from 0.5 μm to 2.5 μm and a grating period ranging from 0.5 μm to 0.6 μm.

Original languageEnglish
Pages (from-to)678-682
Number of pages5
JournalOptics Communications
Issue number2
StatePublished - 15 Sep 2006


  • Apertures
  • Diffraction theory
  • Surface waves


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