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Optical Engineering

Nonparaxial optical vortices and Kummer laser beams
Author(s): Alexander Alexeevich Kovalev; Viktor V. Kotlyar; Anton G. Nalimov
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Paper Abstract

Two approaches to describe nonparaxial optical vortices were considered. One approach is to use a revised Kirchhoff integral, which does not neglect the relief of an optical element. Using this integral and the finite-difference time-domain method it is shown that an optical vortex generated by a refractive spiral plate with a relief step has an asymmetric profile. The annular diffraction pattern in the vortex beam cross-section is found to be disturbed not only for the near-field diffraction but also for the middle-field diffraction, at a distance of several Fresnel lengths. Another approach is to solve the Helmholtz equation without any approximations. An analytical solution to describe propagation of a light beam in the positive direction of the optical axis was found. The complex amplitude of such a beam is found to be in direct proportion to the product of two linearly independent solutions of Kummer’s differential equation. Relationships for a particular case of such beams—namely, the Hankel-Bessel (HB) beams—are deduced. The autofocusing of the HB beams is studied.

Paper Details

Date Published: 10 April 2013
PDF: 10 pages
Opt. Eng. 52(9) 091716 doi: 10.1117/1.OE.52.9.091716
Published in: Optical Engineering Volume 52, Issue 9
Show Author Affiliations
Alexander Alexeevich Kovalev, Image Processing Systems Institute (Russian Federation)
Viktor V. Kotlyar, Image Processing Systems Institute (Russian Federation)
Anton G. Nalimov, Image Processing Systems Institute (Russian Federation)


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