Chiro-optical effects offer a wide range of potential applications in nanophotonics, such as advanced imaging and molecular sensing and separation. Flat single-layer metasurfaces composed of subwavelength meta-atoms have gained significant attention due to their exceptional characteristics in light–matter interactions. Although metasurface-based devices have manipulated electromagnetic waves, the compact on-chip realization of giant chiro-optical effects remains a challenge at optical frequencies. In this work, we experimentally and numerically demonstrate an all-dielectric metasurface to realize large chiro-optical effects in the visible regime. Notably, the proposed strategy of utilizing achiral nanofins instead of conventional chiral structures provides an extra degree of design freedom. The mutual coupling between carefully engineered nanofins produces constructive and destructive interference, leading to the asymmetric transmission of 70% and average circular dichroism exceeding 60%. We investigate the underlying mechanism behind the chiro-optical effects using the theory of multipolar decomposition. The proposed design mechanism maximizes the chiro-optical response through a single-layer metasurface with potential applications in high-efficiency integrated ultrathin polarization rotators and shapers, chiral polarizers for optical displays, chiral beam splitters, and chiral sensors.

中文翻译：

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基于多极共振的单层介电超表面中的巨大手性光学响应

手性光学效应在纳米光子学中提供了广泛的潜在应用，例如先进的成像和分子传感与分离。由亚波长超原子组成的扁平单层超表面由于其在光-物质相互作用中的特殊特性而获得了极大的关注。尽管基于超表面的设备已经操纵了电磁波，但在光学频率下实现巨大手性光学效应的紧凑型片上实现仍然是一个挑战。在这项工作中，我们通过实验和数值演示了一种全介电超表面，以在可见光范围内实现大的手性光学效应。值得注意的是，所提出的利用非手性纳米鳍代替传统手性结构的策略提供了额外的设计自由度。精心设计的纳米鳍之间的相互耦合产生建设性和破坏性干扰，导致 70% 的不对称透射率和超过 60% 的平均圆二色性。我们使用多极分解理论研究手性光学效应背后的潜在机制。所提出的设计机制通过单层超表面最大化手性光学响应，在高效集成超薄偏振旋转器和整形器、光学显示器的手性偏振器、手性分束器和手性传感器中具有潜在应用。我们使用多极分解理论研究手性光学效应背后的潜在机制。所提出的设计机制通过单层超表面最大化手性光学响应，在高效集成超薄偏振旋转器和整形器、光学显示器的手性偏振器、手性分束器和手性传感器中具有潜在应用。我们使用多极分解理论研究手性光学效应背后的潜在机制。所提出的设计机制通过单层超表面最大化手性光学响应，在高效集成超薄偏振旋转器和整形器、光学显示器的手性偏振器、手性分束器和手性传感器中具有潜在应用。