Abstract
In this paper, two simple cascaded metasurfaces capable of generating vortex beams with distinct topological charges (±1,
±3) are proposed and designed. The first metasurface is a plasmonic metasurface which is composed of 21×21 elliptic
nanoslits arrays perforated in an Au film. These nanoslits act as localized space-variant linear polarizers and introduce
Pancharatnam−Berry phase. The second one is an all-dielectric metasurface which consists of 21×21 elliptic silicon
nanopillars arrays on SiO2 substrate. These nanopillars work as space-variant half-wave plates and result in a space-variant
effective birefringence. The cascaded metasurfaces can operate at 1550 nm and the weight spectra of the desired
topological charge can exceed 0.95. The cascaded metasurfaces are designed as transmission-type which makes them
applied to optical fiber system. Multiple topological charges correspond to more channel capacity and different propagation
directions of vortex beams are more suitable for spatial mode multiplexing. Our scheme may be a potential candidate in
integrated optical communication system in future.
Keywords
Plasmonic, All-dielectric, Vortex beam, Polarization.
Citation
XIAODONG ZHANG, JIMIN SHANG, RUILIANG ZHANG, Two cascaded metasurfaces capable of generating vortex beams with distinct topological charges, Optoelectronics and Advanced Materials - Rapid Communications, 15, 9-10, September-October 2021, pp.410-419 (2021).
Submitted at: March 1, 2021
Accepted at: Oct. 7, 2021