Enhanced Sensitivity in Dual-Core Photonic Crystal Fiber Plasmonic Biosensor

The constraints inherent in prism-based surface plasmon resonance (SPR) biosensors, stemming from their bulkiness and reliance on optical and mechanical components, have rendered them somewhat impractical for field-based applications. This limitation has catalyzed the development of SPR biosensors based on optical fibers. This article presents the development of a highly sensitive SPR biosensor using a dual-core photonic crystal fiber (PCF) in which a deposited silver layer, serving as a plasmonic material, surrounds the PCF structure to monitor changes in the refractive index of the surrounding environment. Additionally, a thin layer of titanium dioxide (TiO₂) is applied over the silver to prevent oxidation. In terms of wavelength and amplitude sensitivity, the biosensor demonstrates a maximum of 6000 nm/RIU and 330 RIU⁻¹, respectively. Additionally, real-world condition modeling demonstrated that the designed device can distinguish between healthy skin cells and cancerous cells. Thus, it is a promising candidate for applications in drug detection, biological sensing, and other analytical scenarios.