Detection of E-coli Bacteria Utilizing High Performance Ag-BaTiO3 Heterostructure Based Plasmonic Sensor

A systematic investigation of the performance of CaF₂-Ag-BaTiO₃ heterostructure based SPR sensor has been performed. The article focuses on the point that a suitable dielectric layer and precise optimization process can lead to high performance. E-coli bacterial is considered as analyte medium. The sensor design is optimized by simultaneous varying the thickness of Ag (d_M) and BaTiO₃ (d_A) at wavelength (λ) = 1000 nm which provided an optimized figure of merit (FOM) of 4510 RIU⁻¹ at d_M = 48.1 and d_A = 3.2 nm. Further, FOM is again enhanced by simultaneous optimization of wavelength and thickness of BaTiO₃ which provided an FOM of 9108 RIU⁻¹ at λ = 992 and d_A = 3.3 nm at fixed d_M = 48.1 nm. This is designated as final optimum radiation damping (ORD) condition for the proposed sensor design. The power loss curve and normalized electric field are plotted at ORD condition leads to the FWHM of 0.0200° and sensitivity of 182.17 deg. RIU⁻¹ with power loss ratio of 2.59 and field enhancement factor of 1.06. The combined performance factor (CPF) at optimized parameters is 24276.79 µm⁴/RIU which enables the realization of sensor more practically.