Tapered Fiber Probe Modified by Ag Nanoparticles for SERS Detection

A tapered optical fiber fabricated by a simple chemical etching method and modified with Ag nanoparticles (AgNPs) by chemical deposition was evaluated for surface-enhanced Raman scattering (SERS). The fiber probe was used for SERS measurements in both direct and remote scattering modes, yielding desired performance in both scattering configurations. The state of the obtained AgNPs made a significant contribution to the high sensitivity of SERS to Rhodamine 6G (R6G) molecules (down to a concentration of 10^?7 M), and the substrate had an analyst enhancement factor (AEF) on the order of ～10⁸. Meanwhile, the SERS intensity during the evaporation process was investigated, showing a good stability at the later stage of the evaporation process. The fiber SERS probes demonstrated good reproducibility with the average relative standard deviation (RSD) values being less than 0.2 for the major Raman peaks.