Detection of pathogens in water using long range surface plasmon resonance biosensor: Numerical investigation

This work presents a numerical demonstration for improving the imaging sensitivity of long-range surface plasmon (LRSPR) biosensors using the prism 2S2G/cytop/Cu/Gr (Graphene)/sensing medium (SM) configuration. In the suggested LRSPR biosensor, the imaging sensitivity is compared to that of the traditional surface plasmon sensor (tSPR) through numerical analysis. The proposed LRSPR sensor reaches 4655.7/RIU as its maximum imaging sensitivity for detecting E. coli bacteria. The maximum electric field intensity is found at the interface between the Cu/SM in the tSPR sensor and the Gr/SM in the proposed sensor. For pathogens detection such as pure-water (P.W.), Vibrio-Cholera (V.C.), Escherichia-Coli (E.coli), Bacillus-Anthracis (B.A.), and Enterococcus -aecalis (B.F), the penetration depth (PD) for the LRSPR sensor are 304.46 nm, 955.45 nm, 961.45 nm, 957.44 nm and 1050.7 nm. The LRSPR sensor's effectiveness in biosensing applications is further demonstrated by its figure of merit (FoM) for the detection of pathogens bacteria, which is 291.8/RIU (V.C), 781.5/RIU (E.coli), 59.28/RIU(B.A.) and 738.5/RIU (E.F.), respectively.