Beaming of electromagnetic waves emitted through a subwavelength annular aperture


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Caglayan H. , Bulu I., Ozbay E.

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, vol.23, no.3, pp.419-422, 2006 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 3
  • Publication Date: 2006
  • Doi Number: 10.1364/josab.23.000419
  • Title of Journal : JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
  • Page Numbers: pp.419-422

Abstract

We study the diffraction of electromagnetic waves from subwavelength metallic circular apertures in the microwave spectrum. The theoretical and experimental demonstration of the near- and far-field electromagnetic distributions for subwavelength circular annular apertures and circular annular apertures surrounded by concentric periodic grooves are reported here. The metallic samples had a subwavelength hole with a diameter of 8 mm and had concentric grooves with a periodicity of 16 mm. 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 degrees. This represents a fourfold reduction when compared with the angular divergence of the beam transmitted from the subwavelength circular aperture. (c) 2006 Optical Society of America.