In this study, we investigated a compact refractive index (RI) sensor containing two concentric double-square resonators with plasmonic metal/insulator/metal (MIM) structures to facilitate the sensing of human blood groups. The sensing surveys were conducted using the finite difference time domain method. Intensive coupling occurred due to momentum matching between the equivalent modes of the square resonators. The results demonstrated that the modes of resonance had high contraction ratios in this device and increasing the material RI in the resonators led to remarkable red shifts of the dip wavelengths. The sensing performance was enhanced by using two multiple concentric resonators to effectively increase the strength of the light–analyte interaction, which is useful for sensing applications. Our proposed nano-sensor obtained sensitivity, sensing resolution, and figure of merit values of 1380 nm/RIU, 7.24 × 10⁻⁴ RIU, and 104 RIU^‒1, respectively. The effects of the geometrical variables on the output spectra were studied in detail. Furthermore, this MIM-based sensor may have potential applications in highly integrated optical circuits for monitoring and filtering tasks.

在这项研究中，我们研究了一种紧凑型折射率（RI）传感器，该传感器包含两个具有等离子金属/绝缘体/金属（MIM）结构的同心双平方谐振器，以促进人体血型的感测。感测是使用时域有限差分法进行的。由于方形谐振器等效模式之间的动量匹配，发生了强耦合。结果表明，谐振模式在该器件中具有高的收缩率，并且谐振器中材料RI的增加导致下降波长的红移显着。通过使用两个多个同心谐振器有效地提高了光-分析物相互作用的强度，从而提高了传感性能，这对于传感应用很有用。我们提出的纳米传感器获得了灵敏度，^{分别为−4} RIU和104 RIU ^‒1。详细研究了几何变量对输出光谱的影响。此外，这种基于MIM的传感器可能在高度集成的光学电路中具有潜在的应用，可用于监视和过滤任务。