TiO2-FG-based plasmonic sensor with enhanced figure of merit for sensing applications: A numerical approach

A refractive index-based surface plasmon resonance sensor using a multilayer heterostructure in the Kretschmann configuration is proposed for the near-infrared region. In the proposed configuration, aluminum is used as a plasmonic metal, titanium dioxide is used as a dielectric layer, and a fluorinated graphene (FG) layer is used as a 2D nanomaterial to enhance the performance parameters. A thorough comparative study is conducted between popularly used titanium compounds: Titanium dioxide (TiO₂) and Titanium disilicide (TiSi₂). For the proposed SPR sensor, each layer is engineered and optimized on the grounds of linewidth, detection accuracy (DA), and Figure of Merit (FOM), which are the critical performance parameters. To this end, the geometrical parameters are calculated using the transfer matrix method and analyzed meticulously to find the optimum trade-off points. The proposed sensor is numerically tested efficiently to sense different concentrations of hemoglobin in human blood. For the angle interrogation technique at the wavelength of 1550 nm, the sensor provides an enhanced FOM of 462.8 RIU⁻¹ and a DA of 4 degrees⁻¹. Thus, the proposed design opens a broader window for bio-sensing applications because of the advantages TiO₂ and FG layers offer in enhancing the sensing parameters.