The optical devices play an important role in different fields, such as refractive index detection in food processing and biochemical industry. In our work, a novel nanoscale optical structure, composed metal-insulator-metal (MIM) waveguide with a stub and a horizontal number eight-shape cavity (HNEC), is presented. The transmission properties of this structure are investigated detailedly by using finite element method (FEM). The effects of geometric parameters on sensing performance are studied detailedly. Moreover, the influences of asymmetric resonator caused by shifting central rectangular cavity of HNEC on transmission spectrum are discussed. The changing HNEC resonator have different effects on different resonance dips. Further more, the application of this intriguing structure served as refractive index sensor is studied, whose maximum sensitivity can reach to 1500 nm/RIU with FOM of 75. Therefore, this structure will contribute to the development of miniaturization of the optical device.

中文翻译：

---

用于传感应用的 MIM 波导系统中具有水平数八形腔的可调谐纳米传感器

光学器件在不同领域发挥着重要作用，例如食品加工和生化工业中的折射率检测。在我们的工作中，提出了一种新颖的纳米级光学结构，由金属-绝缘体-金属 (MIM) 波导组成，具有短截线和水平八字形腔 (HNEC)。使用有限元方法（FEM）详细研究了该结构的传输特性。详细研究了几何参数对传感性能的影响。此外，还讨论了HNEC中心矩形腔移动引起的非对称谐振器对透射光谱的影响。变化的 HNEC 谐振器对不同的谐振倾角有不同的影响。此外，研究了这种有趣的结构作为折射率传感器的应用，