High-efficiency ultra-broadband orbital angular momentum beam generators enabled by arrow-based fractal metasurface
High-efficiency ultra-broadband orbital angular momentum beam generators enabled by arrow-based fractal metasurface
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DOI：
10.1088/1361-6463/ac2201
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发表时间：
2021-11-25
影响因子：
3.4
通讯作者：
Ding, Jun
中科院分区：
文献类型：
--
作者：
Liu, Yiting;Xie, Rensheng;Ding, Jun
携带轨道角动量（OAM）的涡旋光束非常重要，因为它能够将通信系统的信道容量从微波扩展到光学领域。本工作利用分形方法设计了单层超宽带元原子。基于箭头的分形元原子的反射共极化幅度在6至19.7 GHz的频率范围内可以超过0.9，并且通过旋转结构可以实现完整的2 pi相位控制。基于所提出的超原子，设计了基于超表面的涡旋光束发生器。作为说明性示例，设计、制造和测量了模式为+1的基于超表面的OAM光束发生器。实验和模拟结果相互吻合，证明了所提出的高效超宽带超表面的实用性。
Vortex beams carrying orbital angular momentum (OAM) are of great importance owing to the capacity to expand channel capacity of communication systems from microwave to optical regimes. In this work, a single-layer ultra-broadband meta-atom is designed by using the method of fractal. The reflected co-polarization amplitude of the arrow-based fractal meta-atom can exceed 0.9 in a frequency range from 6 to 19.7 GHz and the complete 2 pi phase control can be achieved by rotating the structure. Based on the proposed meta-atom, metasurface-based vortex beam generators are designed. As an illustrative example, a metasurface-based OAM beam generator with a mode of +1 is designed, fabricated, and measured. Both the experimental and simulated results match well with each other, proving the practicability of the proposed high-efficiency ultra-broadband metasurface.