Simulation of Surface Plasmon Resonance (SPR) of Silver with Titanium Oxide as a Bi-Layer Biosensor

Abstract

Surface plasmon resonance (SPR) is a highly sensitive method for monitoring changes in the optical characteristics that are near the sensor surface. It can be stimulated by an evanescent field that comes from the total internal reflection of the backside of the sensor surface in the Otto setup. In this setup, SPR can be used to build a simulation model at different thicknesses of titanium oxide (TiO2) (dTiO2 = 50 nm) and silver (Ag) (dAg = 10–80 nm) layers, which are deposited on the semicircular glass prism D-ZLAF50 by using water as a sensing medium. The surface plasmon resonance angle (θSPR) properties were calculated; SPR was not observed in the ultraviolet region (300 nm) or in the infrared region at 800 nm, but appeared strongly in the visible region at 600 and 700 nm and in the infrared region (900 and 1000 nm). The best sensitivity (S = 140) can be observed in the visible region, where the values of SPR dip length (Ld) and full-width half maximum (FWHM) are very good at silver layer thicknesses 40–60 nm; therefore, the proposed sensor can be used in the visible and infrared regions at the wavelengths 600, 700, 900, and 1000 nm.

Silver Prism Interface Plasmon Resonance for Biosensor in Ir-Visible Spectrum Region

“…Computer models show that this multi-layer sensor's electric field is up to 50% larger than that of a gold film sensor. Kadhum et al, (2021) [6] carried out a simulated investigation of layers of silver (dAg = 10-80 nm) and titanium oxide (dTiO2 = 50 nm) applied to the semicircular glass prism D-ZLAF50 to detect water. SPR was observed in the visible spectrum at 600 and 700 nm and in the infrared spectrum; its characteristics were estimated at 900 and 1000 nm.…”