Anomalous Bessel vortex beam: modulating orbital angular momentum with propagation

Zero-order and higher-order Bessel beams are well-known nondiffracting beams. Namely, they propagate with invariant profile (intensity) and carry a fixed orbital angular momentum. Here, we propose and experimentally study an anomalous Bessel vortex beam. Unlike the traditional Bessel beams, the anom...

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Bibliographic Details
Published inNanophotonics (Berlin, Germany) Vol. 7; no. 3; pp. 677 - 682
Main Authors Yang, Yuanjie, Zhu, Xinlei, Zeng, Jun, Lu, Xingyuan, Zhao, Chengliang, Cai, Yangjian
Format Journal Article
LanguageEnglish
Published Berlin De Gruyter 23.02.2018
Walter de Gruyter GmbH
Subjects
Angular momentum
Beams (radiation)
diffraction
fractional topological charge
Optical trapping
optical vortex beam
orbital angular momentum
Propagation
Quantum phenomena
Vortices
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Summary:Zero-order and higher-order Bessel beams are well-known nondiffracting beams. Namely, they propagate with invariant profile (intensity) and carry a fixed orbital angular momentum. Here, we propose and experimentally study an anomalous Bessel vortex beam. Unlike the traditional Bessel beams, the anomalous Bessel vortex beam carries decreasing orbital angular momentum along the propagation axis in free space. In other words, the local topological charge is inversely proportional to the propagation distance. Both the intensity and phase patterns of the generated beams are measured experimentally, and the experimental results agree well with the simulations. We demonstrate an easy way to modulate the beam’s topological charge to be an arbitrary value, both integer and fractional, within a continuous range. The simplicity of this geometry encourages its applications in optical trapping and quantum information, and the like.
ISSN:2192-8614
2192-8606
2192-8614
DOI:10.1515/nanoph-2017-0078