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Proceedings Paper

Beam shaping with vectorial vortex beams under low numerical aperture illumination condition
Author(s): Jianning Dai; Qiwen Zhan
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Paper Abstract

In this paper we propose and demonstrate a novel beam shaping method using vectorial vortex beam. A vectorial vortex beam is laser beam with polarization singularity in the beam cross section. This type of beams can be decomposed into two orthogonally polarized components. Each of the polarized components could have different vortex characteristics, and consequently, different intensity distribution when focused by lens. Beam shaping in the far field can be achieved by adjusting the relative weighing of these two components. As one example, we study the vectorial vortex that consists of a linearly polarized Gaussian component and a vortex component polarized orthogonally. When such a vectorial vortex beam is focus by low NA lens, the Gaussian component gives rise to a focal intensity distribution with a solid centre while the vortex component gives rise to a donut distribution with hollow dark center. The shape of the focus can be continuously varied by continuously adjusting the relative weight of the two components. Under appropriate conditions, flat top focusing can be obtained. We experimentally demonstrate the creation of such beams with a liquid crystal spatial light modulator. Flattop focus obtained by vectorial vortex beams with topological charge of +1 has been obtained.

Paper Details

Date Published: 11 September 2008
PDF: 8 pages
Proc. SPIE 7062, Laser Beam Shaping IX, 70620D (11 September 2008); doi: 10.1117/12.793157
Show Author Affiliations
Jianning Dai, Univ. of Dayton (United States)
Qiwen Zhan, Univ. of Dayton (United States)

Published in SPIE Proceedings Vol. 7062:
Laser Beam Shaping IX
Andrew Forbes; Todd E. Lizotte, Editor(s)

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