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Plasmonic structures with extraordinary transmission and highly directional beaming properties
Author(s) -
Caglayan Humeyra,
Bulu Irfan,
Ekmel Ozbay
Publication year - 2006
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.22015
Subject(s) - optics , aperture (computer memory) , microwave , physics , surface plasmon , plasmon , grating , coupling (piping) , concentric , coaxial , materials science , geometry , acoustics , telecommunications , mathematics , quantum mechanics , metallurgy , computer science
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. Microwave Opt Technol Lett 48: 2491–2496, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22015