Highly sensitive plasmonic MIM-based refractive index sensor with comb-shaped cavities for pressure sensing

This work presents a new sensor structure including a metal-insulator-metal (MIM) waveguide made from silver and two comb-shaped cavities. The top cavity has 10 teeth, while the bottom cavity consists of 8. Both the waveguide and cavities are filled with air. The sensor’s design enables multi-resonance transmission characteristics, which are analyzed through simulations using the finite element method (FEM). The sensor’s sensitivity is assessed using simulations for four distinct configurations. Simulation studies demonstrate that the number of teeth substantially influences the refractive index sensitivity. The refractive index sensitivities for the first, second, and third peaks in the transmission diagram are 6595 ± 147.79, 2543.33 ± 87.39, and 1771.68 ± 4.19 nm/RIU, respectively. Furthermore, the suggested sensor exhibits pressure sensing capabilities, achieving a maximum pressure sensitivity of 346.50 ± 12.68 nm/MPa. The proposed design delivers high sensitivity and compactness, making it ideal for integration into nanoscale pressure-sensing platforms.