In this paper, we present a novel strategy for fabricating surface-enhanced Raman scattering (SERS) optical probe modified monolayer gold nanoparticles (AuNPs) by a seed-mediated growth method. The morphology and optical properties of the samples were characterized by transmission electron microscopy, scanning electron microscopy, and UV-visible absorption spectroscopy. The results show that the resulting probes exhibit high sensitivity with a detection limit down to 10 − 9 m o l / L for Methylene Blue solution and 10 − 8 m o l / L for both Crystal Violet and Rhodamine 6G solutions. Furthermore, the probes show an excellent reproducibility (relative standard deviation of 9.2% at 1621 c m − 1 ) and good stability, and the SERS spectra can be reproduced after storing the probes for one month in air. Finally, by finite-element simulations, we investigate the electromagnetic field distribution of the fiber facet modified with AuNPs. This work provides a promising potential of prepared SERS fiber probes and has broad application prospects in food safety, pesticide residue analysis, and environmental surveillance.

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In this work, we report a strategy of Ag nanoparticles (Ag NPs) coated tapered optical ber probes by nite difference time domain (FDTD) simulations. Investigation shows that the ber tip decorated Ag NPs have excellent electric eld enhancement and con nement of light capabilities compared with ber tips. Moreover, we demonstrate the effect of key parameters such as tip radius, conical angle, Ag NPs size and gaps between them on the eld enhanced utilizing typical excitation wavelength of 532, 633 and 785 nm. To further improve the electrical eld effect, a noble metal substrate is introduced below the tip apex which exhibits a higher eld enhancement generated by tip-substrate coupling. The presence of the Au substrate does not lead to a signi cant change in the plasma characteristic peak of the probes at 490 nm. This study provides a useful reference for the fabrication of tapered optical ber with plasmonic nanostructures and the design of robust tapered ber-optic Raman sensors.

In this work, we report a strategy of Ag nanoparticles (Ag NPs) coated tapered optical fiber probes by finite difference time domain (FDTD) simulations. Investigation shows that the fiber tip decorated Ag NPs have excellent electric field enhancement and confinement of light capabilities compared with fiber tips. Moreover, we demonstrate the effect of key parameters such as tip radius, conical angle, Ag NPs size and gaps between them on the field enhanced utilizing typical excitation wavelength of 532, 633 and 785 nm. To further improve the electrical field effect, a noble metal substrate is introduced below the tip apex which exhibits a higher field enhancement generated by tip-substrate coupling. The presence of the Au substrate does not lead to a significant change in the plasma characteristic peak of the probes at 490 nm. This study provides a useful reference for the fabrication of tapered optical fiber with plasmonic nanostructures and the design of robust tapered fiber-optic Raman sensors.