Li Shiqing, Tsakmakidis Kosmas L, Jiang Tao, Shen Qian, Zhang Hang, Yan Jinhua, Sun Shulin, Shen Linfang
Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China.
Section of Condensed Matter Physics, Department of Physics, National and Kapodistrian University of Athens Panepistimioupolis, Athens, GR-157 84, Greece.
Nat Commun. 2024 Jul 16;15(1):5992. doi: 10.1038/s41467-024-50287-z.
Metasurfaces are capable of fully reshaping the wavefronts of incident beams in desired manners. However, the requirement for external light excitation and the resonant nature of their meta-atoms, make challenging their on-chip integration. Here, we introduce the concept and design of a fresh class of metasurfaces, driven by unidirectional guided waves, capable of arbitrary wavefront control based on the unique dispersion properties of unidirectional guided waves rather than resonant meta-atoms. Upon experimentally demonstrating the feasibility of our designs in the microwave regime, we numerically validate the introduced principle through the design of several microwave meta-devices using metal-air-gyromagnetic unidirectional surface magneto-plasmons, agilely converting unidirectional guided modes into the wavefronts of 3D Bessel beams, focused waves, and controllable vortex beams. We, further, numerically demonstrate sub-diffraction focusing, which is beyond the capability of conventional metasurfaces. Our unfamiliar yet practical designs may enable full, broadband manipulation of electromagnetic waves on deep subwavelength scales.
超表面能够以期望的方式完全重塑入射光束的波前。然而，对外部光激发的要求及其超原子的共振特性，使得它们的片上集成具有挑战性。在此，我们介绍一类新型超表面的概念和设计，这类超表面由单向导波驱动，基于单向导波独特的色散特性而非共振超原子实现任意波前控制。在实验证明我们的设计在微波频段的可行性之后，我们通过设计几种使用金属 - 空气 - 旋磁单向表面磁等离子体的微波超器件，从数值上验证了所引入的原理，这些器件能灵活地将单向导模转换为三维贝塞尔光束、聚焦波和可控涡旋光束的波前。此外，我们还从数值上证明了亚衍射聚焦，这是传统超表面所无法实现的。我们这种新颖却实用的设计可能实现深亚波长尺度上对电磁波的全频段操控。
