Plasmonic structures with extraordinary transmission and highly directional beaming properties
Author
Cağlayan, H.
Bulu, I.
Özbay, Ekmel
Date
2006Source Title
Microwave and Optical Technology Letters
Print ISSN
0895-2477
Publisher
Wiley Periodicals
Volume
48
Issue
12
Pages
2491 - 2496
Language
English
Type
ArticleItem Usage Stats
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Abstract
We studied the grating-coupling phenomena between surface plasmons and electromagnetic waves in the microwave spectrum. We first present the experimental and theoretical results of an enhanced microwave transmission though a subwavelength circular annular aperture with and without metallic gratings. We demonstrate that a 145-fold enhancement factor could be obtained with a subwavelength circular annular aperture that was surrounded by periodic metallic gratings. This was assisted by the guided mode of the coaxial waveguide and by coupling to the surface plasmons. We present the angular transmission distributions from circular annular apertures, and circular annular apertures surrounded by concentric periodic grooves. At the surface mode resonance frequency, the transmitted electromagnetic waves from the subwavelength circular annular aperture surrounded by concentric periodic grooves have a strong angular confinement with an angular divergence of ±3°. We demonstrate that only the output surface is responsible for the beaming effect. Furthermore, we present the field distributions and showed that there is no beaming effect at the off-resonance frequency. © 2006 Wiley Periodicals, Inc.
Keywords
Annular apertureBeaming
Enhanced transmission
Grating
Subwavelength aperture
Surface plasmon
Diffraction gratings
Electromagnetic wave transmission
Electromagnetic waves
Microwaves
Annular aperture
Beaming
Enhanced transmission
Subwavelength aperture
Surface plasmon resonance