Transverse Focal Shift in Vortex Beams

The transverse focal shift (TFS) is a phenomenon that the maximum of a focused field does not occur at the geometrical focus, but is moved a short distance transversely in the focal plane. In this paper, the TFS of vortex beams in a high numerical aperture system is investigated. Four typical types...

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Main Authors: Xinying Zhao, Xiaoyan Pang, Jingcheng Zhang, Guobin Wan
Format: Article
Language:English
Published: IEEE 2018-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/8264749/
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author Xinying Zhao
Xiaoyan Pang
Jingcheng Zhang
Guobin Wan
author_facet Xinying Zhao
Xiaoyan Pang
Jingcheng Zhang
Guobin Wan
author_sort Xinying Zhao
collection DOAJ
description The transverse focal shift (TFS) is a phenomenon that the maximum of a focused field does not occur at the geometrical focus, but is moved a short distance transversely in the focal plane. In this paper, the TFS of vortex beams in a high numerical aperture system is investigated. Four typical types of incident vortex beams are selected and the intensity distributions and the vortices behaviors in the focal region are discussed analytically and numerically. It is found that there are three main parameters, the topological charge, the initial positions of the vortices, and the semiaperture angle influencing the TFS in different ways, and the TFS even can be observed when the vortices annihilate in the focal plane. Our results also show that the intensity maximum can move from the <inline-formula><tex-math notation="LaTeX">$y$</tex-math></inline-formula>-axis, <inline-formula> <tex-math notation="LaTeX">$x$</tex-math></inline-formula>-axis to the geometrical focus, or move from <inline-formula> <tex-math notation="LaTeX">$+y$</tex-math></inline-formula>-axis to <inline-formula><tex-math notation="LaTeX">$-y$ </tex-math></inline-formula>-axis in different cases, which may have implications in optical trapping.
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publishDate 2018-01-01
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spelling doaj-art-99bea7d3e68c413793a2a8d3016c7c432025-08-20T03:31:24ZengIEEEIEEE Photonics Journal1943-06552018-01-0110111710.1109/JPHOT.2018.27955978264749Transverse Focal Shift in Vortex BeamsXinying Zhao0Xiaoyan Pang1https://orcid.org/0000-0001-8265-0952Jingcheng Zhang2Guobin Wan3School of Electronics and Information, Northwestern Polytechnical University, Xi&#x2019;an, ChinaSchool of Electronics and Information, Northwestern Polytechnical University, Xi&#x2019;an, ChinaSchool of Electronics and Information, Northwestern Polytechnical University, Xi&#x2019;an, ChinaSchool of Electronics and Information, Northwestern Polytechnical University, Xi&#x2019;an, ChinaThe transverse focal shift (TFS) is a phenomenon that the maximum of a focused field does not occur at the geometrical focus, but is moved a short distance transversely in the focal plane. In this paper, the TFS of vortex beams in a high numerical aperture system is investigated. Four typical types of incident vortex beams are selected and the intensity distributions and the vortices behaviors in the focal region are discussed analytically and numerically. It is found that there are three main parameters, the topological charge, the initial positions of the vortices, and the semiaperture angle influencing the TFS in different ways, and the TFS even can be observed when the vortices annihilate in the focal plane. Our results also show that the intensity maximum can move from the <inline-formula><tex-math notation="LaTeX">$y$</tex-math></inline-formula>-axis, <inline-formula> <tex-math notation="LaTeX">$x$</tex-math></inline-formula>-axis to the geometrical focus, or move from <inline-formula> <tex-math notation="LaTeX">$+y$</tex-math></inline-formula>-axis to <inline-formula><tex-math notation="LaTeX">$-y$ </tex-math></inline-formula>-axis in different cases, which may have implications in optical trapping.https://ieeexplore.ieee.org/document/8264749/Singular opticsdiffraction theoryoptical vortextransverse focal shift
spellingShingle Xinying Zhao
Xiaoyan Pang
Jingcheng Zhang
Guobin Wan
Transverse Focal Shift in Vortex Beams
IEEE Photonics Journal
Singular optics
diffraction theory
optical vortex
transverse focal shift
title Transverse Focal Shift in Vortex Beams
title_full Transverse Focal Shift in Vortex Beams
title_fullStr Transverse Focal Shift in Vortex Beams
title_full_unstemmed Transverse Focal Shift in Vortex Beams
title_short Transverse Focal Shift in Vortex Beams
title_sort transverse focal shift in vortex beams
topic Singular optics
diffraction theory
optical vortex
transverse focal shift
url https://ieeexplore.ieee.org/document/8264749/
work_keys_str_mv AT xinyingzhao transversefocalshiftinvortexbeams
AT xiaoyanpang transversefocalshiftinvortexbeams
AT jingchengzhang transversefocalshiftinvortexbeams
AT guobinwan transversefocalshiftinvortexbeams