Studying the Optical Properties of Nanostructure Au/TiO2 Bi-layer Films using the SPR Technique for Biosensing Applications

Surface plasmon resonance (SPR) is an optical technique that can be used for sensitive optical sensor and biosensor applications. Surface plasmon resonance (SPR) biosensors consisting of alternate layers of gold (Au) and Titanium dioxide (TiO2) thin film have been proposed as a high sensitivity property. Simulation analysis (in Matlab program) has been made for SPR of gold layer with thickness (10, 30 and 50 nm) and (TiO2) layer with different eight thicknesses (from 10 to 100 nm), which deposited on high refractive index glasses (N_LASF9 glass prism), while the final sensing medium is the air. The analysis achieved for different wavelengths in the visible band (500-700 nm) and different refractive index (0, 0.04, 0.08 and 0.12). The properties of SPR angle θSPR have been calculated from the incident angle θSPR plot. The SPR sensitivity (S) calculated within this study. The results show that the best sensitivity and maximum sensitivity is (116.66) for thickness TiO2=40 nm, and thickness Au =50 nm at wavelength 700 nm. for the studied refractive index.