Optical Fiber Probe Based on Localized Surface Plasmon Resonance of Gold Nanostructures for Chemical Sensing

In this study, we present an experimental investigation of highly sensitive optical fiber sensors utilizing localized surface plasmon resonance (LSPR), achieved by depositing gold nanoparticles (NP) onto uncladded silica multi-mode fiber. This setup takes advantage of the unique optical characteristics of optical fiber sensors and plasmonic resonance provided by gold NPs. The experimental results demonstrated a maximum sensitivity of about 130 nm/RIU in water solution, for an LSPR wavelength at 560 nm. As a study case, the sensor was used to detect Thiram, a common agricultural pesticide, exhibiting a wide detection range from 10 nM to 100 µM, with a significant wavelength shift up to 4 nm. Moreover, a preliminary study involving the use of nanostar-based optical fiber sensors is comparatively provided. The highest sensitivity makes this approach highly promising for a range of applications, including environmental monitoring, biomedical diagnostics, and chemical detection.