Ma Zhiyao, Tian Tian, Liao Yuxuan, Feng Xue, Li Yongzhuo, Cui Kaiyu, Liu Fang, Sun Hao, Zhang Wei, Huang Yidong
Department of Electronic Engineering, Tsinghua University, Beijing, China.
Nat Commun. 2024 Sep 27;15(1):8370. doi: 10.1038/s41467-024-52676-w.
Metasurfaces with tunable functionalities are greatly desired for modern optical system and various applications. To increase the operating channels of polarization-multiplexed metasurfaces, we proposed a structure of N cascaded dual-channel metasurfaces to achieve 2 electrically switchable channels without intrinsic loss or cross-talk for certain functionalities, including beam steering, vortex beam generation, lens, etc. As proof of principles, we have implemented a 3-layer setup to achieve 8 channels. In success, we have demonstrated two typical functionalities of vortex beam generation with switchable topological charge of l = -3 ~ +4 or l = -1 ~ -8, and beam steering with the deflection direction switchable in an 8×1 line or a 4×2 grid. We believe that our proposal would provide a practical way to significantly increase the scalability and extend the functionality of polarization-multiplexed metasurfaces. Although this method is not universal, it is potential for the applications of LiDAR, glasses-free 3D display, OAM (de)multiplexing, and varifocal meta-lens.
具有可调功能的超表面对于现代光学系统和各种应用来说是非常需要的。为了增加偏振复用超表面的工作通道，我们提出了一种由N个级联双通道超表面组成的结构，以实现2个电可切换通道，对于某些功能（包括光束转向、涡旋光束产生、透镜等）不存在固有损耗或串扰。作为原理验证，我们实现了一个三层设置以实现8个通道。成功地，我们展示了两种典型功能：涡旋光束产生，其拓扑电荷l可在-3至+4或-1至-8之间切换；光束转向，其偏转方向可在8×1线或4×2网格中切换。我们相信我们的提议将提供一种切实可行的方法来显著提高偏振复用超表面的可扩展性并扩展其功能。虽然这种方法并不通用，但它在激光雷达、无眼镜3D显示、轨道角动量（解）复用和变焦超透镜的应用中具有潜力。
