Triple-Independently Tunable MIM Waveguide for High-Sensitivity Fano Resonance Refractive Index Sensing

This study proposes a surface plasmonic MIM waveguide configuration integrating E-shaped and Analogy Ψ-Shaped resonant cavities, demonstrating exceptional sensitivity and triply adjustable resonance control. The Fano resonance phenomena and transmission properties are analyzed via finite-difference time-domain (FDTD) and perfectly matched layer (PML) boundary absorption simulations, achieving the maximum quality factors and refractive index sensitivities are found to be $1.45 \times 10^{4}$ and $1338 \mathrm{~nm}$/RIU, respectively. Moreover, the triple independent tuning enhances the sensing efficiency, providing valuable insights for the design of efficient refractive index sensors.