Li Jiu-Sheng, Chen Jun-Zhao
Opt Express. 2021 Aug 16;29(17):27332-27339. doi: 10.1364/OE.434206.
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.
本文提出了一种新型超表面，在x-（y-）偏振太赫兹波入射下，它能够同时产生具有预先设计的不同反射方向的轨道角动量（OAM）光束、多光束和多模式。单元结构由作为顶层的空心耶稣结构十字、聚四氟乙烯基底层和金金属底板组成。推导了相位梯度分布理论并用于设计多功能OAM超表面。所提出的超表面在1太赫兹频率下分别产生两个OAM模式l = 1的OAM光束和四个l = -1的OAM光束。类似地，在1.3太赫兹频率下，对于x-（y-）偏振波入射，设计的超表面分别产生两个l = -2的OAM光束和一个l = 2的OAM光束。由于每个OAM模式都可以用作独立的数字信息编码通道，因此所设计的多功能OAM超表面在未来太赫兹通信中具有广阔的应用前景。
