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ISRN Optics
Volume 2013 (2013), Article ID 185495, 6 pages
http://dx.doi.org/10.1155/2013/185495
Research Article

Thin Light Tube Formation by Tightly Focused Azimuthally Polarized Light Beams

Image Processing Systems Institute of the Russian Academy of Sciences, Molodogvardeiskaya Street 151, Samara 443001, Russia

Received 21 June 2013; Accepted 14 July 2013

Academic Editors: A. K. Dharmadhikari and D. Poitras

Copyright © 2013 Svetlana N. Khonina and Andrey V. Ustinov. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Theoretical and numerical analysis of the transmission function of the focusing system with high numerical aperture was conducted. The purpose of the study was to form a thin light tube in a focal area using the azimuthally polarized radiation. It was analytically shown that, due to destructive interference of two beams formed by two narrow rings, it is possible to overcome not only the full aperture diffraction limit but also the circular aperture limit. In this case, however, the intensity at the center of the focal plane is significantly reduced, which practically leads to the tube rupture. It was numerically shown that long thin one-piece tubes may be formed through the aperture apodization with diffractive axicon phase function or with complex transmission function of Laguerre-Gaussian or Airy-Gaussian beams.