Plasmonic nano-disc-shaped optical fiber probe

Miniature plasmonic fiber probes hold vast potential in nanophotonics and label-free biosensing. However, their further use and development are hindered by complex fabrication processes. Therefore, developing low-cost and simple manufacturing methods is crucial for advancing plasmonic fiber probes. Therefore, we propose a disk-shaped multimode fiber probe based on hybrid plasmonic modes of surface plasmon polaritons (SPP) and localized surface plasmon resonance (LSPR). Using a simple nanosphere self-assembly technique to fabricate silver disk arrays (SDAs) and wet-transfer with polyvinyl alcohol (PVA) to the fiber end, large-scale production can be achieved. The SDAs achieve a refractive index sensitivity of up to 625.4 nm/RIU, while the fiber probe demonstrates a refractive index sensitivity of 329.8 nm/RIU. Additionally, it shows a significant spectral response to variations in PVA film thickness, with a humidity sensitivity of approximately 0.3 nm/%RH. This study not only emphasizes the versatility of SDAs in optical sensing applications but also offers novel and effective methods for the development of miniature plasmonic fiber probes.