Metasurfaces have powerful light field manipulation capabilities and have been researched and developed extensively in various fields. With an increasing demand for diverse functionalities, terahertz (THz) metasurfaces are also expanding their domain. In particular, integrating different functionalities into a single device is a compelling domain in metasurfaces. In this work, we demonstrate a functionally decoupled THz metasurface that can incorporate any two functions into one metasurface and switch dynamically through external excitation. This proposed metasurface is formed by the combination of split-ring resonators and phase change material vanadium dioxide (VO2). It operates in the single-ring resonant mode and double-ring resonant mode with varying VO2 in insulating and metallic states, respectively. More importantly, the phase modulation is independent in two operating modes, and both cover a 360° cross-polarized phase with efficient polarization conversion. This characteristic makes it obtain arbitrary independent phase information on the metasurface with different modes to switch dual functions dynamically. Here, we experimentally demonstrate the functions of a tunable focal length and large-angle focus deflection of a THz off-axis parabolic mirror to verify the dual-function switching characteristics of the functionally decoupled metasurface. The functionally decoupled metasurface developed in this work broadens the way for the research and application of multifunctional modulation devices in the THz band.

Xuan Cong;Hongxin Zeng;Shiqi Wang;Qiwu Shi;Shixiong Liang;Jiandong Sun;Sen Gong;Feng Lan;Ziqiang Yang;Yaxin Zhang

Terahertz Science and Technology Research Center, University of Electronic Science and Technology of China, Chengdu 610000, China;College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China;National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050051, China;Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China;Yangtze Delta Region Institute (HuZhou), University of Electronic Science and Technology of China, Huzhou 313001, China

光子学研究（英文）

[1]Xuan Cong;Hongxin Zeng;Shiqi Wang;Qiwu Shi;Shixiong Liang;Jiandong Sun;Sen Gong;Feng Lan;Ziqiang Yang;Yaxin Zhang-.Dynamic bifunctional THz metasurface via dual-mode decoupling)[J].光子学研究（英文）,2022(09):2008

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