Fiber Optic Sensors Based on Localized Surface Plasmon Resonance (LSPR) of Gold Nanostars

We investigate here Localized Surface Plasmon Resonance (LSPR)-based fiber optic sensors grounded uncladded multi-mode silica fibers with gold nanostars (NSs) and spherical nanoparticles (NPs) deposition. By tuning NS morphology, we achieve precise LSPR control, reaching 560 nm/RIU sensitivity at 810 nm, significantly outperforming NPs. As benchmark molecule, the sensor detects Thiram pesticide across 10 pM-100 μM range with a 0.3 pM detection limit, demonstrating exceptional analytical performance. The branched NS architecture leverages enhanced local field effects for superior sensitivity compared to conventional NPs, while the fiber-optic design ensures robustness and field deployability. Overall, this platform combines simplicity, cost-effectiveness, and tunable sensitivity, making it ideal for circumstantial monitoring, biomedical diagnostics, and chemical sensing.