In spite of having very large real part of permittivity, Rhodium (Rh) is rarely used as a plasmonic metal in surface plasmon resonance (SPR) based sensing applications. Here, we theoretically present a simple SPR based prism-coupled refractive index sensor in Kretschmann geometry utilizing a bimetallic layer of Rhodium (Rh) and Silver (Ag) as plasmonic metal layer on the base of the SF10 glass prism. In addition Silicon is used as an upper most layer, which not only protects the oxidation-prone Ag film but also enhances the field and thereby the sensor’s performance. Each of the layers is optimized for maximum sensitivity in the visible region at 632 nm wavelength of excitation. The sensor exhibits an extremely high sensitivity of 229 degree/refractive index unit (RIU) for analyte refractive indices (RIs) varying from 1.33 to 1.37 RIU.

中文翻译：

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用于水性样品的高灵敏度双金属等离子体传感探针

尽管具有非常大的介电常数实部，但铑 (Rh) 在基于表面等离子体共振 (SPR) 的传感应用中很少用作等离子体金属。在这里，我们从理论上提出了一种基于 Kretschmann 几何结构的简单 SPR 棱镜耦合折射率传感器，利用铑 (Rh) 和银 (Ag) 的双金属层作为 SF10 玻璃棱镜底部的等离子体金属层。此外，硅用作最上层，不仅可以保护易氧化的银膜，还可以增强电场，从而增强传感器的性能。每一层都经过优化，可在 632 nm 激发波长的可见光区实现最大灵敏度。该传感器对 1.33 至 1.37 RIU 的分析物折射率 (RI) 具有 229 度/折射率单位 (RIU) 的极高灵敏度。