A Highly Sensitive Structure Based on Prism, Silver, and Titanium Dioxide for Biochemical Sensing Applications

In this paper, a refractive index (RI) sensor with prism configuration is proposed and numerically investigated for sensing applications. The sensor design is based on a BK7 prism, silver (Ag), and titanium dioxide (TiO2). Important enhancement in the sensitivity and reflection deep is obtained by optimizing some geometric and optical parameters. The transfer matrix method (TMM) is employed to investigate the reflectance of the sensor at wavelength interrogation. RI sensitivity (SRI), figure of merit (FoM), and quality factor (QF) are three important parameters that are considered to determine the design performance. The SRI, FoM, and QF offered by the nanostructure are 6300 nm/RIU, 52.24 RIU-1, and 11.04, respectively, when the refractive index is varied from 1.33 to 1.41. We have successfully detected various chemical entities in an aqueous solution, such as heavy metals, lactose, ethanol, and sodium chloride (NaCl), using a wavelength interrogation-based SPR biosensor.