In this paper, a refractive index sensor based on three circular rings coupled with a straight metal-insulator-metal (MIM) waveguide is presented. At near-infrared (NIR) spectrum, the spectral characteristics of the sensor are extensively analyzed using the finite element method (FEM). Moreover, the refractive index sensing property is comprehensively investigated by altering the design parameters. The results show a maximum sensitivity of 3573.3 nm/RIU with a figure of merit of 21.9, which is suitable for gas-sensing applications. The proposed sensor has also displayed prominent tolerance against manufacturing defects. Furthermore, the sensor proves to be highly sensitive for the label-free detection of blood components and DNA hybridization.

在本文中，提出了一种基于三个圆环与直金属-绝缘体-金属 (MIM) 波导耦合的折射率传感器。在近红外 (NIR) 光谱中，使用有限元方法 (FEM) 广泛分析了传感器的光谱特性。此外，通过改变设计参数全面研究了折射率传感特性。结果显示最大灵敏度为 3573.3 nm/RIU，品质因数为 21.9，适用于气体传感应用。所提出的传感器还显示出对制造缺陷的显着容忍度。此外，该传感器被证明对血液成分的无标记检测和 DNA 杂交高度敏感。