Gaussian laser beam transformation into an optical vortex beam by helical lens |
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Authors: | Ljiljana Janicijevic |
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Affiliation: | Faculty of Natural Sciences and Mathematics, Institute of Physics, University “Ss Cyril and Methodius”, Skopje, Republic of Macedonia |
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Abstract: | In this article, we investigate the Fresnel diffraction characteristics of the hybrid optical element which is a combination of a spiral phase plate (SPP) with topological charge p and a thin lens with focal length f, named the helical lens (HL). As incident a Gaussian laser beam is treated, having its waist a distance ζ from the HL plane and its axis passing through the centre of the HL. It is shown that the SPP introduces a phase singularity of pth order to the incident beam, while the lens transforms the beam characteristic parameters. The output light beam is analyzed in detail: its characteristic parameters and focusing properties, amplitude and intensity distributions and the vortex rings profiles, and radii, at any z distance behind the HL plane, as well as in the near and far field. |
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Keywords: | Fresnel diffraction helical lens Gaussian laser beam vortex |
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