摘要
Recent advances of space-time-coding digital metasurfaces demonstrate powerful capabilities in the generation of nonlinear harmonics and the accurate control of the corresponding wavefronts. However, to date the near field manipulation and the experiment characterization are still not explored. In this paper, we propose a space-timedigital coding metasurface to realize accurate manipulation of the near fields at the fundamental and +1 st(-1 st)harmonics simultaneously, by properly controlling the initial phase and time delay of the time varying reflectivity.A novel mapping system is established to measure the nonlinear near field distributions of multiharmonics. Both the simulation and experimental results demonstrate the validity of the proposed method.
基金
111 Project (111-2-05)
National Natural Science Foundation of China (11227904, 61722106,61731010)
National Key Research and Development Program of China (2017YFA0700201, 2017YFA0700202,2017YFA0700203, 2018YFA0701904)。
