Refractive index, temperature and pressure three-mode sensing design based on Silver-Nitrogen-Graphene coupled resonators

The lack of multimode Fano resonances supported by existing plasma devices limits their accuracy and functionality. In this work, we proposed a three-mode plasma sensor of refractive index, temperature and pressure based on Silver-Nitrogen-Graphene (SNG) coupled resonator. By designing the geometric parameters and resonant cavity material, a unique resonator construction is determined. Six independently tunable Fano resonances are excited, which support the three-mode sensing. We achieve refractive index, temperature, and pressure sensitivity of 812 nm/RIU, 273 pm/K, and 18.27 nm/Mpa respectively. This sensor also has excellent Q-factor of 100.88, FOM of 175.59 and other performance indicators. The temperature drift compensation algorithm is adopted to reduce the interference of zero drift on the single parameter measurement. Finite-difference time-domain (FDTD) algorithm is used in the work. Relationship between the wavelength of the Fano resonance and the geometric parameter of the coupled resonator and the resonant cavity material is further studied. This work provides theoretical and technical support for the design of multifunctional and high-precision multimode plasma sensors.