Manipulation of Orbital Angular Momentum Spectrum Using Shape-Tailored Metasurfaces

Ling-Jun Yang; Sheng Sun; Wei E. I. Sha

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arXiv · 2103.03352

Manipulation of Orbital Angular Momentum Spectrum Using Shape-Tailored Metasurfaces

Ling-Jun Yang·Sheng Sun·Wei E. I. Sha

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Abstract

Vortex beams carrying orbital angular momentum (OAM) have been widely applied in various electromagnetic, optical, and quantum systems. A tailored OAM spectrum composed of several specific modes as expected holds a promise for expanding the degrees of freedom of the systems. However, such a broadband high-purity tailored spectrum is difficult to be achieved by the present devices, where the broadband amplitude manipulation has not been explored yet. In this work, inspired by the envelope-modulation theory, an elegant and universal way to manipulate the OAM spectrum in wide bandwidth is proposed by using a shape-tailored metasurface. Firstly, the rotating meta-atoms on a triangular lattice are proved to have smaller coupling distortion than that on a square lattice, and this behavior is critical for high-purity vortex spectrum generation by the Pancharatnam-Berry-based metasurfaces. Secondly, a universal modulation relation is established between the spatial arrangement of metasurfaces and the generated vortex beams. Finally, the broadband modulated OAM spectra and the comb-like OAM spectra are theoretically and experimentally demonstrated by the shape-tailored metasurfaces. The proposed amplitude-modulation scheme offers a novel concept and engineering route to manipulate the OAM spectrum in wide bandwidth, which could promote the development of OAM-based applications.

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BibTeX RIS

Ling-Jun Yang, Sheng Sun, Wei E. I. Sha. 2021-01-26. Manipulation of Orbital Angular Momentum Spectrum Using Shape-Tailored Metasurfaces. https://arxiv.org/abs/2103.03352

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