Design and analysis of plasmonic sensor in communication band with gold grating on nitride substrate

Grating coupled nanostructures are integral part of advanced plasmonic sensors for bio-sensing applications. In this work, gold gratings on dielectric substrate (e.g., GaN, MN, and Si3N4) based plasmonic sensor is simulated and analyzed in optical communication band for refractive index sensing with spectral interrogation. The sensor simulation is carried out with rigorous coupled wave analysis (RCWA). The influence of grating variables on resonance behavior and sensing performance of the grating structure is also studied. A significantly large sensitivity of 1140 nm/RIU is achieved with a very high precision (in terms of as small curve width as 4.20 nm). The results indicate that Au grating on GaN substrate can provide a high sensing performance for a broad range of analyte refractive indices. The sensor provides comparatively better performance than the existing grating based plasmonic sensors. The possibility of self-referenced sensing is also explored.