Gold nanowire-functionalized D-Shaped PCF-SPR sensor for ultrasensitive detection of biomarkers

An ex-centric core photonic crystal fiber (PCF)-based high-performance surface plasmon resonance (SPR ) biosensor with a surface-functionalized, externally coated dual gold nanowires. The new design is based on an asymmetric core displacement mechanism that helps to strengthen the coupling between the core-guided mode and surface plasmon polaritons (SPPs), possessing strong field confinement due to resonance generation without internal metal deposition or the D-shaped polishing of the geometry. A manifest finite element method (FEM) provides outstanding sensing parameters, as the optimum wavelength sensitivity was 51,200 nm RIU−1, amplitude sensitivity was 1248.5 RIU−1 and the figure of merit (FOM) was a high 179.33 RIU−1 over a refractive index range of 1.34–1.39. The optimized structure with a nanowire diameter of 0.6 0 m and pitch of 2.0 0 m also proves the ability to attain the minimum resolution threshold of 1.18 × 10−4 RIU, which verifies the ability to detect ultra-low levels of biochemical analyte. The model has better dual-mode performance, wider RI range and simpler fabrication compared with the recent SPR sensors. The given conceptual sensor is highly suited to the disciplines of real-time biomedical diagnostics, environment monitoring, and integrated lab-on-chip, whose nature demands high sensitivity and compactness.