Self-referenced plasmonic sensor with TiO2 grating on thin Au layer: simulated performance analysis in optical communication band

Dielectric grating–based surface plasmon resonance (SPR) sensors with self-referenced capability are relatively less explored. A self-referenced SPR sensor incorporating titanium oxide (TiO2) grating on thin gold (Au) film atop dielectric substrates is proposed in the optical communication band. The rigorous coupled wave analysis (RCWA) method is used for sensor simulation and evaluation of performance parameters. The finite-element method-based field strength analysis is performed to study the behavior of two plasmon modes (analyte mode and substrate mode) at respective resonance conditions. Further, the influence of various grating variables on sensor performance is analyzed. As a major result, in the optical communication band, an average spectral sensitivity and SPR curve width of 693.88 nm/RIU and 26.03 nm, respectively, are achieved for the optimized values of grating variables. Proposed TiO2 grating on Au film atop SiO2 substrate can provide greater sensitivity than the existing grating-based plasmonic sensors for a broad range of analyte refractive indices.