Geometric phases are very important for achieving broadband functional metasurfaces, which are usually obtained by rotating meta‐atoms. However, such rotation‐induced geometric phases are inherently spin‐coupled, with the same magnitude and opposite sign for left‐ and right‐handed circularly polarized (LCP and RCP) waves, which is unfavorable for designing different functions for LCP and RCP waves. Therefore, it is desirable that geometric phases for single circular polarization be explored. In this work, it is first proposed to achieve geometric phases for single polarization by delicately designing curvature of the meta‐atom, which only imparts geometric phase to RCP or LCP waves. Then, spin‐decoupled metasurfaces are designed by hybridizing such curvature‐induced geometric phases and conventional rotation‐induced geometric phases. Two prototypes of dual‐channel functional metasurfaces are designed, fabricated, and measured. Both the simulated and experimental results verify the spin‐decoupled phase modulation. This work expands the methods of phase engineering in metasurfaces and may find wide applications in communication, sensing, imaging, and others.

中文翻译：

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通过混合曲率和旋转诱导的几何相来实现自旋解耦超表面

几何相对于实现宽带功能超表面非常重要，这通常是通过旋转超原子获得的。然而，这种旋转引起的几何相位本质上是自旋耦合的，左旋和右旋圆偏振（LCP和RCP）波具有相同的幅度和相反的符号，这不利于为LCP和RCP波设计不同的函数。因此，需要探索单圆偏振的几何相位。在这项工作中，首次提出通过精心设计元原子的曲率来实现单偏振的几何相位，仅将几何相位赋予RCP或LCP波。然后，通过混合这种曲率引起的几何相位和传统的旋转引起的几何相位来设计自旋解耦超表面。设计、制造和测量了两个双通道功能超表面原型。模拟和实验结果都验证了自旋解耦相位调制。这项工作扩展了超表面中的相工程方法，并可能在通信、传感、成像等领域得到广泛应用。