Transverse Focal Shift in Vortex Beams

Xinying Zhao, Xiaoyan Pang*, Jingcheng Zhang, Guobin Wan

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

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 y-axis, x-axis to the geometrical focus, or move from +y-axis to-y-axis in different cases, which may have implications in optical trapping.

Original languageEnglish
Article number8264749
Pages (from-to)1-18
Number of pages18
JournalIEEE Photonics Journal
Volume10
Issue number1
DOIs
Publication statusPublished - 23 Jan 2018

Funding

Manuscript received December 14, 2017; revised January 11, 2018; accepted January 15, 2018. Date of publication January 23, 2017; date of current version February 6, 2018. This work was supported by the National Natural Science Foundation of China (11504296, 11604264) and Natural Science Basic Research Plan in Shaanxi Province of China (2016JQ1011, 2016JQ1021). Corresponding author: Xiaoyan Pang (email: xypang@nwpu.edu.cn).

FundersFunder number
Natural Science Basic Research Plan in Shaanxi Province of China2016JQ1021, 2016JQ1011
National Natural Science Foundation of China11604264, 11504296

    Keywords

    • diffraction theory
    • optical vortex
    • Singular optics
    • transverse focal shift

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