The plasmonic functional lens can realize an efficient and functional focusing of surface plasmon polaritons (SPPs), making it have great potential in applications including nano-electron point sources, smart pixels, and particle manipulation. Here, we report for the first time a novel plasmonic functional lens constructed via a nano-dichroic element. The results show that the wavelength-selective nano-focusing of SPPs in the plasmonic functional lens can be achieved. Different from the conventional plasmonic lens that equally splits SPP power to propagate inward and outward from the boundaries, the plasmonic functional lens directs all of the SPP power of the matched wavelength inward for the focusing, resulting in higher collecting efficiency and SPP focusing intensity. Furthermore, we have demonstrated that a much higher focal spot intensity can be obtained even under the condition of a smaller inner radius. These findings provide a new way for the design of plasmonic functional lenses and can be facilitated to develop high-efficiency miniaturized focusing devices.

中文翻译：

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通过纳米二向色元件构建的高效等离子体功能透镜

等离子体功能透镜可以实现表面等离子体激元（SPP）的高效和功能聚焦，使其在纳米电子点源、智能像素和粒子操纵等应用中具有巨大的潜力。在这里，我们首次报告了一种通过纳米二向色元件构建的新型等离子体功能透镜。结果表明，可以实现等离子体功能透镜中 SPP 的波长选择性纳米聚焦。不同于传统的等离子透镜将 SPP 功率从边界向内和向外传播，等离子体功能透镜将匹配波长的所有 SPP 功率向内引导以进行聚焦，从而获得更高的收集效率和 SPP 聚焦强度。此外，我们已经证明，即使在较小的内半径条件下，也可以获得更高的焦斑强度。这些发现为等离子体功能透镜的设计提供了一种新方法，并有助于开发高效的小型化聚焦装置。