KRETSCHMANN CONFIGURATION BASED SPR SENSORS WITH IMPROVED PERFORMANCE

Abstract

The industry of sensing devices is very versatile in the current era of fast-growing technology. The major requirement from any sensing application is that the sensor should be efficient, reliable, durable, compact and cost effective. The field of surface plasmon resonance (SPR) based sensors has seen a rise in research interest over the past two decades due to the simplicity of implementation, high sensitivity and detection accuracy. In this work, a theoretical modeling of SPR based sensors was performed using kretschmann configuration. Simulation of the various multi-layered plasmonic structures was performed using MATLAB. Transfer matrix method was used for sensor modeling. These structures were investigated by angular interrogation technique at 637 nm wavelength for refractive index sensing. We tried multiple structures with different materials to form multi-layer sensors. In this study, light is incident from SF11 prism side. High dielectric film coatings on metal films can enhance the performance of SPR sensors. So, we studied the effect of the Titanium Oxide (TiO2) and Magnesium fluoride (MgF2) films on the performance of the SPR based sensors. We found that when the thickness of silver film and TiO2 layer were optimized properly then the presence of TiO2 film layer on the silver film can enhance the Figure of merit (FOM) of the SPR based sensors by more than 25 times in comparison to Ag- SF11 prism based SPR sensors. For SF11 prism/ Ag (50.7 nm thickness)/ TiO2 (115 nm thickness)/ analyte (water) structure, FOM came out to be 2511.86 which is very high in comparison to Ag- SF11 prism based and other similar kind of SPR sensors.