Yi Cheng, Wang Zejing, Shi Yangyang, Wan Shuai, Tang Jiao, Hu Wanlin, Li Zile, Zeng Yongquan, Song Qinghua, Li Zhongyang
Electronic Information School, Wuhan University, Wuhan, 430072, China.
Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Light Sci Appl. 2025 Aug 5;14(1):262. doi: 10.1038/s41377-025-01955-2.
Classified as a non-Hermitian system, topological metasurface is one of the ideal platforms for exploring a striking property, that is, the exceptional point (EP). Recently, creating and encircling EP in metasurfaces has triggered various progressive functionalities, including polarization control and optical holographic encoding. However, existing topological metasurfaces mostly rely on plasmonic materials, which introduce inevitable ohmic losses and limit their compatibility with mainstream all-dielectric meta-devices. Additionally, conventional free-space configurations also hinder the integration of multiple meta-devices in compact platforms. Here, an on-chip topological metasurface is experimentally demonstrated to create and engineer the topological phase encircling the EP in all-dielectric architecture. By massively screening the Si meta-atom geometry on the SiN waveguide, a 2π-topological phase shift is obtained by encircling the EP. Through combining with the Pancharatnam-Berry (PB) phase, we decouple the orthogonal circular polarization channels and unfold the independent encoding freedom for different holographic generations. As a proof of concept, the proposed on-chip topological metasurface enables floating holographic visualizations in real-world scenarios, functioning as practical augmented reality (AR) functionalities. Such the all-dielectric on-chip scheme eliminates ohmic losses and enables compatible integration with other on-chip meta-devices, thus suggesting promising applications in next-generation AR devices, multiplexing information storage, and advanced optical displays.
拓扑超表面被归类为非厄米系统，是探索一种显著特性——即奇异点（EP）的理想平台之一。最近，在超表面中创建和环绕奇异点引发了各种先进功能，包括偏振控制和光学全息编码。然而，现有的拓扑超表面大多依赖于等离子体材料，这会引入不可避免的欧姆损耗，并限制它们与主流全介质超器件的兼容性。此外，传统的自由空间配置也阻碍了多个超器件在紧凑平台中的集成。在此，通过实验展示了一种片上拓扑超表面，用于在全介质架构中创建和设计环绕奇异点的拓扑相位。通过在氮化硅波导上大量筛选硅超原子几何结构，环绕奇异点可获得2π拓扑相移。通过与潘查拉特纳姆 - 贝里（PB）相位相结合，我们解耦了正交圆偏振通道，并为不同的全息生成展开了独立的编码自由度。作为概念验证，所提出的片上拓扑超表面在现实场景中实现了浮动全息可视化，具备实用的增强现实（AR）功能。这种全介质片上方案消除了欧姆损耗，并能够与其他片上超器件兼容集成，从而在下一代AR设备、复用信息存储和先进光学显示方面展现出广阔的应用前景。
