Liu Ji, Qi Jurui, Yao Jin, Hu Wenman, Zhang Dajun, Xu He-Xiu, Wang Xiong
School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Air Force Engineering University, Xi'an 710051, China.
Nanophotonics. 2022 Apr 4;11(10):2369-2379. doi: 10.1515/nanoph-2022-0066. eCollection 2022 May.
Electromagnetic vortex carries the orbital angular momentum, one of the most fundamental properties of waves. The order of such vortex can be unbounded in principle, thus facilitating high-capability wave technologies for optical communications, photonic integrated circuits and others. However, it remains a key challenge to generate the high-order vortex beams in a reconfigurable, broadband and cost-effective manner. Here, inspired by the balanced-ternary concept, we demonstrate the reconfigurable generation of order-controllable vortices via cascaded -layer metasurfaces. We theoretically showed that different vortex modes can be generated by cascading metasurfaces, each one serving as an individual vortex beam generator for the order of ( = 0,1,2 …, ). As a proof-of-concept demonstration, a reconfigurable generation of 26 different vortex beams, with orders from 1 to 13 and from -1 to -13, is showcased in a broad millimeter-wave region by a cascade of 3 metasurfaces. Our method can be easily extended to vortex beam generator of arbitrary orders in a reconfigurable and easily implementable manner, paving a new avenue towards tremendous practical applications.
电磁涡旋携带着轨道角动量，这是波的最基本特性之一。这种涡旋的阶数原则上可以是无界的，从而有利于用于光通信、光子集成电路等的高容量波技术。然而，以可重构、宽带且经济高效的方式产生高阶涡旋光束仍然是一个关键挑战。在此，受平衡三进制概念的启发，我们展示了通过级联层超表面实现阶数可控涡旋的可重构产生。我们从理论上表明，通过级联超表面可以产生不同的涡旋模式，每个超表面都作为阶数为 （ = 0,1,2 …, ）的单个涡旋光束发生器。作为概念验证演示，通过级联 3 个超表面在宽毫米波区域展示了 26 种不同涡旋光束的可重构产生，其阶数从 1 到 13 以及从 -1 到 -13。我们的方法可以很容易地以可重构且易于实现的方式扩展到任意阶数的涡旋光束发生器，为众多实际应用开辟了一条新途径。
