Li JS, Chen JZ. Multi-beam and multi-mode orbital angular momentum by utilizing a single metasurface.
OPTICS EXPRESS 2021;
29:27332-27339. [PMID:
34615151 DOI:
10.1364/oe.434206]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
This paper proposes a novel metasurface that can simultaneously generate orbital angular momentum (OAM) beams with pre-designed different reflection directions, multi-beam and multi-mode under x-(y-) polarized terahertz wave incidence. The configuration of unit cell is made up of a hollow cross of Jesus structure as top layer, a PTFE substrate layer and a gold metal bottom plate. Theory of phase gradient distribution is derived and used to design multifunctional OAM metasurface. The proposed metasurface generates two OAM beams with OAM mode l = 1 and four OAM beams with l = -1 at frequency of 1 THz, respectively. Similarly, at frequency of 1.3 THz, the designed metasurface produces two OAM beams with l = -2 and an OAM beam with l = 2 for x-(y-) polarized wave incidence, respectively. Since each OAM mode can be used as an independent digital information coding channel, the designed multifunctional OAM metasurface has a wide application prospect in future terahertz communication.
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