Hybrid nanostructure with two-dimensional grating for resonance waves self-referenced sensing

Self-referenced sensors have attracted significant interest in recent years due to their ability to provide more reliable detection results than conventional sensors. In this paper, we propose a hybrid structure based on a two-dimensional grating surface for self-referenced refractive index sensing in the near-infrared operating band. The hybrid structure can support the metal-assisted guided-mode and Fabry–Pérot resonances. Meanwhile, the resonance mechanism of the proposed structure is analyzed in detail through the electric field distribution characteristics, and the feasibility of the structure as self-referenced sensing is also confirmed. In addition, the influences of structural parameters, structure shape, and polarization angle on the optical properties are systematically discussed. Notably, calculations at different refractive indices of the analytes show that the structure has a more stable reference signal and better sensing performance than previously reported self-referenced sensors, with a sensitivity and figure of merit of 680 nm/RIU and 1852 RIU−1, respectively. These results illustrate that the proposed structure can provide more accurate measurements in some unstable measurement environments, implying its promising application in the fields of biological, pharmaceutical, and chemical sensing.