A self-referencing plasmonic platform is proposed and analyzed. By introducing a thin gold layer below a periodic two-dimensional nano-grating, the structure supports multiple modes including localized surface plasmon resonance (LSPR), surface plasmon resonance (SPR), and Fabry-Perot resonances. These modes get coupled to each other creating multiple Fano resonances. A coupled mode between the LSPR and SPR responses is spatially separated from the sensor surface and is not sensitive to refractive index changes in the surrounding materials or surface attachments. This mode can be used for self-referencing the measurements. In contrast, the LSPR dominant mode shifts in wavelength when the refractive index of the surrounding medium is changed. The proposed structure is easy to fabricate using conventional lithography and electron beam deposition methods. A bulk sensitivity of 429 nm/RIU is achieved. The sensor also has the ability to detect nanometer thick surface attachments on the top of the grating.

中文翻译：

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自引用等离子阵列传感器

提出并分析了自参考等离子体平台。通过在周期性二维纳米光栅下方引入薄金层，该结构支持多种模式，包括局部表面等离子体激元共振（LSPR），表面等离子体激元共振（SPR）和Fabry-Perot共振。这些模式相互耦合，产生多个Fano共振。LSPR和SPR响应之间的耦合模式在空间上与传感器表面分离，并且对周围材料或表面附件中的折射率变化不敏感。此模式可用于自参考测量。相反，当周围介质的折射率改变时，LSPR主模在波长上移动。所提出的结构易于使用常规光刻和电子束沉积方法来制造。达到429 nm / RIU的整体灵敏度。该传感器还具有检测光栅顶部纳米级表面附着物的能力。