Metasurfaces are paving the way to improve traditional optical components by integrating multiple functionalities into one optically flat metasurface design. We demonstrate the implementation of a multifunctional gap surface plasmon-based metasurface that in reflection mode splits orthogonal linear light polarizations and focuses them into different focal spots. The fabricated configuration consists of 50 nm thick gold nanobricks with different lateral dimensions organized in an array of 240 nm × 240 nm unit cells on top of a 50 nm thick silicon dioxide layer, which is deposited on an optically thick reflecting gold substrate. Our device features high efficiency (up to ∼65%) and polarization extinction ratio (up to ∼30 dB), exhibiting broadband response in the near-infrared band (750–950 nm wavelength) with the focal length dependent on the wavelength of the incident light. The proposed optical component can be forthrightly integrated into photonic circuits or fiber-optic devices.

中文翻译：

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多功能元镜：偏振分离和聚焦

超颖表面通过将多种功能集成到一个光学平坦的超颖表面设计中，为改善传统光学组件铺平了道路。我们演示了基于多功能间隙表面基于等离激元的超颖表面的实现，该超颖表面在反射模式下将正交线性光偏振分裂并将其聚焦到不同的焦点上。制成的配置由50 nm厚的二氧化硅层顶部的50 nm厚的金纳米砖组成，这些金纳米砖具有不同的横向尺寸，排列成240 nm×240 nm晶胞阵列，并沉积在光学厚的反射金基板上。我们的设备具有高效率（高达〜65％）和极化消光比（高达〜30 dB），在近红外波段（波长750-950 nm）具有宽带响应，焦距取决于入射光的波长。所提出的光学组件可以直接集成到光子电路或光纤设备中。