Ultra-sensitive refractive index detection with gold-coated PCF-based SPR sensor

This study introduces an innovative photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor, notable for its sophisticated design and exceptional performance, utilizing gold as the plasmonic material. The sensor offers an expanded detection range and outstanding sensitivity, operating within a refractive index range of 1.27 to 1.43. It achieves a remarkable wavelength sensitivity of 157,000 nm/RIU with a resolution of 6.37 × 10⁻⁷ RIU and an amplitude sensitivity of 1263 RIU⁻¹ with a resolution of 7.92 × 10⁻⁵ RIU. Additionally, it boasts a figure of merit (FOM) of 1648, underscoring its superior capability in detecting biomolecular interactions. The suggested design is numerically analysed using the finite element method (FEM) of a gold-coated PCF-based SPR sensor designed for detecting changes in the refractive index (RI) within the range of 1.27 to 1.43. This range is related to various biological and chemical samples, including proteins, DNA, and biochemical analytes typically used in biomedical diagnostics and environmental monitoring. The integration of gold plasmonic elements enhances the sensor's sensitivity and stability while extending its detection capabilities across a broader range, allowing for versatile applications in biomedicine, environmental monitoring, and beyond. This research significantly advances optical biosensing technologies by offering a robust platform for high-precision detection across diverse domains. The sensor's advanced design and performance make it an invaluable tool for applications requiring accurate and reliable detection, driving innovations in areas such as biomedical diagnostics, environmental monitoring, food safety, and pharmaceutical quality control.