Department of Physics
In recent years, optical vortex beams possessing orbital angular momentum have received much attention due to their potential for high-capacity optical communications. This capability arises from the unbounded topological charges of orbital angular momentum (OAM) that provide infinite freedoms for encoding information. The two most common approaches for generating vortex beams are through fork diffraction gratings and spiral phase plates. While realization of conventional spiral phase plate requires complicated 3D fabrication, the emerging field of metasurfaces has provided a planar and facile solution for generating vortex beams of arbitrary orbit angular momentum. Among various types of metasurfaces, the geometric phase metasurface has shown great potential for robust control of light- and spin-controlled wave propagation. Here, we realize a novel type of geometric metasurface fork grating that seamlessly combine the functionality of a metasurface phase plate for vortex-beam generation, and that of a linear phase gradient metasurface for controlling the wave-propagation direction. The metasurface fork grating is therefore capable of simultaneously controlling both the spin and the orbital angular momentum of light.
Geometric metasurface fork gratings for vortex beam generation and manipulation
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SEG. Grant Number: HKUST08 ; EPSRC. Grant Number: EP/J018473/1 ; Opened Fund of the State Key Laboratory on Integrated Optoelectronics. Grant Number: IOSKL2014KF12 ; Research Grant Council of Hong Kong. Grant Number: AoE/P-02/12 ; NSFC. Grant Number: 11274047
This is the accepted version of the following article: Chen, S., Cai, Y., Li, G., Zhang, S. and Cheah, K. W. (2016), Geometric metasurface fork gratings for vortex-beam generation and manipulation. Laser & Photon. Rev., 10: 322–326. doi: 10.1002/lpor.201500259, which has been published in final form at dx.doi.org/10.1002/lpor.201500259. This article may be used for non-commercial purposes in accordance with the Wiley Self-Archiving Policy [olabout.wiley.com/WileyCDA/Section/id-820227.html].
lasmonic metasurface, fork grating, optical vortex
Chen, Shumei, Yuan Cai, Guixin Li, Shuang Zhang, and Kok Wai Cheah. "Geometric metasurface fork gratings for vortex beam generation and manipulation." Geometric metasurface fork gratings for vortex beam generation and manipulation 10.2 (2016): 322-326.