2021/01/26 by Ling‐Jun Yang, Sheng Sun, Yang, Ling-Jun +3
Engineering · Materials Science · Physics and Astronomy · #Advanced Antenna and Metasurface Technologies #Applied Physics (physics.app-ph) #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Orbital Angular Momentum in Optics
paper · pdf · doi:10.48550/arxiv.2103.03352
openalex publication_date 2021/01/26 · openalex created_date 2021/03/15 · openalex updated_date 2026/07/28
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.