Li Yan, Ansari Muhammad Afnan, Ahmed Hammad, Wang Ruoxing, Wang Guanchao, Yu Qunxing, Zhang Chunmei, Chen Shuqi, Chen Xianzhong
Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K.
School of Materials, Zhengzhou University of Aeronautics, Zhengzhou 450015, China.
ACS Photonics. 2024 Sep 20;11(10):4380-4389. doi: 10.1021/acsphotonics.4c01341. eCollection 2024 Oct 16.
Polarization and color play essential roles in understanding optical phenomena and practical applications. Customized three-dimensional (3D) light fields, characterized by specific polarization and color distributions, have garnered growing interest owing to their unique optical attributes and expanded capacity for information encoding. To align with the ongoing trend of compactness and integration, it is desirable to develop lightweight optical elements that can simultaneously control polarization and color in 3D space. Although engineering longitudinally variable 3D optical structures with predesigned color and polarization information can add more degrees of freedom and additional capacity for information encoding, it has not been reported. We propose a metasurface approach to generating multiple 3D polarization knots along the light propagation direction. Each knot features two colors and an engineered 3D polarization profile. Different multicolored 3D polarization knots are obtained by controlling the observation region along the light propagation. Our approach simultaneously combines polarization, color, and longitudinal control in 3D environment, offering extra degrees of freedom for engineering complex vector beams. The unique properties of the developed metadevices, together with the design flexibility and compactness of metasurface, pave the way for polarization systems with small volumes applicable to some areas such as complex structured beams and encryption.
偏振和颜色在理解光学现象及实际应用中起着至关重要的作用。定制的三维（3D）光场，其特征在于特定的偏振和颜色分布，由于其独特的光学属性以及扩展的信息编码能力而受到越来越多的关注。为了顺应紧凑性和集成化的发展趋势，开发能够在三维空间中同时控制偏振和颜色的轻质光学元件是很有必要的。尽管设计具有预先设定颜色和偏振信息的纵向可变三维光学结构可以增加更多的自由度和额外的信息编码能力，但尚未有相关报道。我们提出一种超表面方法，用于沿光传播方向生成多个三维偏振结。每个结具有两种颜色和一个设计好的三维偏振分布。通过控制沿光传播方向的观察区域可获得不同的多色三维偏振结。我们的方法在三维环境中同时结合了偏振、颜色和纵向控制，为设计复杂矢量光束提供了额外的自由度。所开发的超表面器件的独特特性，以及超表面的设计灵活性和紧凑性，为适用于复杂结构光束和加密等领域的小体积偏振系统铺平了道路。
