Conventional beam splitters and wave plates, while being essential components in diverse optical systems, require considerable space, especially when used in combination. Here, we designed and experimentally demonstrated metasurface-enabled efficient broadband beam splitters integrated with quarter-wave plate (QWP) functionality for simultaneous power splitting and circular-to-linear polarization conversion in the near-infrared range. By utilizing two different gap-plasmon meta-atoms, which function as QWPs performing efficient circular-to-linear polarization conversion and provide the phase difference of π between reflected linearly polarized beams, we designed a metasurface that completely suppress the specular reflection (zero-order diffraction) and second-order diffraction, while ensuring efficient and equal beam splitting of a circularly polarized wave into two reflected beams with predesigned directions and well-defined linear-polarization states in the wavelength range of 750–950 nm. The fabricated metasurface exhibits excellent performance of circular-to-linear conversion and power splitting, with efficient suppression of specular reflection (<1%) and splitting efficiencies above 50% for both right and left circularly polarized excitation at the design wavelength of λ = 850 nm. By enabling the combined functionalities of a conventional beam splitter and a QWP, our approach opens up new prospects for advanced research and applications targeting photonics integration and miniaturization.

中文翻译：

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具有超颖表面的宽带分束器与四分之一波片功能集成在一起。

常规的分束器和波片虽然是各种光学系统中必不可少的组件，但它们需要相当大的空间，尤其是在组合使用时。在这里，我们设计并通过实验演示了集成了超表面的高效宽带分束器，该分束器与四分之一波片（QWP）功能集成在一起，可在近红外范围内同时进行功率分配和圆弧到线偏振转换。通过利用两个不同的等离激元子原子，它们充当QWP来执行有效的圆到线偏振转换并提供反射的线偏振光束之间的π相差，我们设计了一个完全抑制镜面反射（零反射）的超表面。阶衍射）和二阶衍射，同时确保将圆偏振波有效且相等地分裂为两个反射光束，并在750-950 nm的波长范围内以预先设计的方向和明确定义的线性偏振状态。制成的超颖表面表现出出色的圆-线性转换和功率分配性能，在设计波长为的情况下，左右圆偏振激发的有效镜面反射抑制能力（<1％）和分离效率均超过50％。λ＝ 850nm。通过启用常规分束器和QWP的组合功能，我们的方法为针对光子集成和小型化的高级研究和应用开辟了新的前景。