Surface optimization of Nano-Structured bimetallic metamaterial on optical fiber for multi-disease sensing through exhaled air

The paper presents the design and proposal of bimetallic [Gold (Au)-Silver (Ag)] metamaterial reinforced with air-filled nano-cuboids. The Au - Ag metamaterial thin films were optimized for a thickness of 40 nm respectively. The films were coated on the core of silica optical fiber acting as a multi-disease sensing element based on surface plasmon resonance (SPR) phenomenon. The analytical model and finite element method (FEM) simulations show the metamaterial sensor has >50% narrower full-width at half-maximum (FWHM) than the planer-bimetallic. The proposed sensor promises the steep SPR-resonant dip with sensitivity >42% when comparing to its planer counterpart. The sensor carries an added advantage of nanostructures by effectively increasing the surface area for the bio-antigen/antibody bindings.