Generation of polarization-multiplexed terahertz orbital angular momentum combs <i>via</i> all-silicon metasurfaces
Ming-Zhe Chong, Yiwen Zhou, Zongkun Zhang, Jin Zhao, Yueyi Zhang, Chong-Qi Zhang, Xiaofei Zang, Chao‐Hai Du, Pu‐Kun Liu, Ming‐Yao Xia
Abstract
Electromagnetic waves carrying orbital angular momentum (OAM), namely OAM beams, are important in various fields including optics, communications, and quantum information.However, most current schemes can only generate single or several simple OAM modes.Multi-mode OAM beams are rarely seen.This paper proposes a scheme to design metasurfaces that can generate multiple polarization-multiplexed OAM modes with equal intervals and intensities (i.e., OAM combs) working in the terahertz (THz) range.As a proof of concept, we first design a metasurface to generate a pair of polarization-multiplexed OAM combs with arbitrary mode numbers.Furthermore, another metasurface is proposed to realize a pair of polarization-multiplexed OAM combs with arbitrary locations and intervals in the OAM spectrum.Experimental results agree well with full-wave simulations, verifying a great performance of OAM combs generation.Our method may provide a new solution to designing high-capacity THz devices used in multi-mode communication systems.