Magneto-plasmonic sensors based on surface plasmon resonance have been studied considerably in recent years, as they feature high sensitivity and ultrahigh resolution. However, the majority of such investigations focus on prism-based sandwich architectures that not only impede the miniaturization of devices but also have a weak transverse magneto-optical Kerr effect (TMOKE) in magnitude. Herein, we theoretically demonstrate a magneto-plasmonic sensor composed of Au/Co bilayer nanodisk arrays on top of optically thick metallic films, which supports a narrow surface plasmon resonance (SPR) with a bandwidth of 7 nm and allows for refractive index sensitivities as high as 717 nm/RIU. Thanks to the high-quality SPR mode, a Fano-like TMOKE spectrum with a subnanometer bandwidth can be achieved in the proposed structure, thereby giving rise to ultrahigh sensing of merit values as large as 7000 in water. Moreover, we demonstrate a large TMOKE magnitude that exceeds 0.6. The value is 1 order of magnitude larger than that of magneto-plasmonic sensors reported. We also demonstrate that the behavior of TMOKE spectra can be controlled by tuning the geometrical parameters of the device including the diameter and thickness of nanodisk arrays. This work provides a promising route for designing magneto-plasmonic sensors based on metasurfaces or metamaterials.

中文翻译：

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面向高性能磁等离子体传感设备的表面晶格共振

近年来，基于表面等离子体共振的磁等离子体传感器具有高灵敏度和超高分辨率，因此得到了大量研究。然而，大多数此类研究都集中在基于棱镜的三明治结构上，这种结构不仅阻碍了设备的小型化，而且在幅度上还具有弱横向磁光克尔效应 (TMOKE)。在此，我们从理论上证明了一种由 Au/Co 双层纳米盘阵列组成的磁等离子体传感器，该传感器由位于光学厚金属膜顶部的 Au/Co 双层纳米盘阵列组成，该传感器支持带宽为 7 nm 的窄表面等离子体共振 (SPR)，并允许折射率灵敏度高达为 717 nm/RIU。由于高质量的 SPR 模式，在所提出的结构中可以实现具有亚纳米带宽的 Fano-like TMOKE 光谱，从而在水中产生高达 7000 的超高检测值。此外，我们展示了超过 0.6 的大 TMOKE 震级。该值比报告的磁等离子体传感器大 1 个数量级。我们还证明了 TMOKE 光谱的行为可以通过调整设备的几何参数来控制，包括纳米盘阵列的直径和厚度。这项工作为设计基于超表面或超材料的磁等离子体传感器提供了一条有前途的途径。我们还证明了 TMOKE 光谱的行为可以通过调整设备的几何参数来控制，包括纳米盘阵列的直径和厚度。这项工作为设计基于超表面或超材料的磁等离子体传感器提供了一条有前途的途径。我们还证明了 TMOKE 光谱的行为可以通过调整设备的几何参数来控制，包括纳米盘阵列的直径和厚度。这项工作为设计基于超表面或超材料的磁等离子体传感器提供了一条有前途的途径。