Metasurfaces with tunable functionalities are greatly desired for modern optical system and various applications. To increase the operating channels of polarization-multiplexed metasurfaces, the authors proposed a structure of N cascaded dual-channel metasurfaces to achieve 2^N electrically switchable channels without intrinsic loss or cross-talk for certain functionalities, including beam steering, vortex beam generation, lens, etc.. As proof of principles, a 3-layer setup is implemented to achieve 8 channels. In success, two typical functionalities of vortex beam generation and beam steering and are demonstrated. By different combination of cascaded metasurfaces, the topological charge of vortex beam generation is switchable within the range of l=-3 ~ +4 or l=-1~ -8, and the deflection direction of beam steering is switchable in an 8×1 line or a 4×2 grid. This proposal would provide a practical way to significantly increase the scalability and extend the functionality of polarization-multiplexed metasurfaces, and be potential for the applications of LiDAR, glasses-free 3D display, OAM (de)multiplexing, and varifocal meta-lens.

This work has been published on Nature Communications at September 27^th, 2024 (https://doi.org/10.1038/s41467-024-52676-w). The first author of this article is Ph.D candidate Zhiyao Ma, while the corresponding authors are Prof. Xue Feng and Prof. Yidong Huang.