The orbital angular momentum (OAM) transformation of optical vortex is realized upon using aluminum metasurfaces with phase distributions derived from the caustic theory. The generated OAM transformation beam has the well-defined Bessel-like patterns with multiple designed topological charges from −1 to +2.5 including both the integer-order and fractional-order optical vortices along the propagation. The detailed OAM transformation process is observed in terms of the variations of both beam intensity and phase profiles. The dynamic distributions of OAM mode density in the transformation are further analyzed to illustrate the conservation of the total OAM. The demonstration of transforming OAM states arbitrarily for optical vortex beams will lead to many new applications in optical manipulation, quantum optics, and optical communication.
The topological charge (TC) inversion of optical vortex is demonstrated along the beam propagation direction by using plasmonic geometric metasurfaces with the initial wave fronts designed from the principle of caustic surface. The detailed TC inversion evolution process is observed together with the transmutation point where the vortex vanishes. The orbital angular momentum (OAM) mode distributions during the TC inversion process are studied to show the dynamic redistributions of OAM mode density between the central area and the surrounding area of the beam with the total OAM conserved. Furthermore, the TC inversion of self‐accelerating vortex beam along the parabolic trajectory is presented. The realization of controlling TC inversion of optical vortex along arbitrary beam trajectory paves the way for many applications with more complex functionalities in optical trapping and manipulation, optical sensing, quantum information and computation, and data communication.
more » « less- NSF-PAR ID:
- 10460120
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Optical Materials
- Volume:
- 7
- Issue:
- 8
- ISSN:
- 2195-1071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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