Plasmonic sensor design: Cu-SiO₂-Ni-black phosphorus for enhanced surface plasmon resonance in visible regime

A novel surface plasmon resonance (SPR) sensor is presented utilizing a BK7 prism, copper (Cu), silicon dioxide (SiO₂), nickel (Ni), and black phosphorus (BP) for enhanced biomolecule sensing in the refractive index (RI) range of 1.33 - 1.335. The combination of Cu and Ni offers strong plasmonic properties, while BP tunable bandgap and superior light-matter interactions significantly improve sensitivity. SiO₂ enhances chemical stability and enables surface functionalization, making the sensor robust for real-world applications. The high sensitivity of 417.11°/RIU is attained with a remarkable quality factor (QF) of 102.19/RIU at minimum reflectance (R_min), outperforming existing SPR sensors in terms of both sensitivity and reliability. The maximum sensitivity of 479.10°/RIU is achieved. The proposed design addresses key challenges in SPR sensing, including environmental stability, layer optimization, and sensitivity enhancement, positioning it as a promising platform for advanced biomolecular detection.