Li Jiu-Sheng, Zhang Li-Na
Opt Express. 2020 Nov 23;28(24):36403-36412. doi: 10.1364/OE.410681.
Orbital angular momentum (OAM) is an effective way to increase wireless communication capacity. The existing OAM mainly focuses on the optical and microwave frequency domain. In this letter, a reflective metasurface is proposed to generate an OAM vortex wave beam in the terahertz region with different topological charges. Under illumination of a circular polarized wave, the proposed metasurface generates the deflected OAM vortex wave beam with topological charges of l=±1 and l=±2 at a wide terahertz band from 0.3THz to 0.45THz. The OAM beam has a high mode purity that is larger than 90% at 0.4THz. Both theoretical prediction and simulated results verify that the designed metasurface can achieve a terahertz vortex wave beam with different OAM topological charges.
轨道角动量（OAM）是增加无线通信容量的一种有效方式。现有的轨道角动量主要集中在光学和微波频域。在本文中，提出了一种反射型超表面，用于在太赫兹频段产生具有不同拓扑电荷的轨道角动量涡旋波束。在圆极化波的照射下，所提出的超表面在0.3太赫兹至0.45太赫兹的宽太赫兹频段内产生拓扑电荷为l = ±1和l = ±2的偏转轨道角动量涡旋波束。该轨道角动量波束在0.4太赫兹时具有大于90%的高模式纯度。理论预测和模拟结果均验证了所设计的超表面能够实现具有不同轨道角动量拓扑电荷的太赫兹涡旋波束。
