The synergy of a plasmonic tip and fiber-based structure light field excitation can provide a powerful tool for Raman examination. Here, we present a method of Raman spectrum enhancement with an Ag-nanoparticles(Ag-NP...The synergy of a plasmonic tip and fiber-based structure light field excitation can provide a powerful tool for Raman examination. Here, we present a method of Raman spectrum enhancement with an Ag-nanoparticles(Ag-NPs)-coated fiber probe internally excited via an azimuthal vector beam(AVB), which is directly generated in a few-mode fiber by using an acoustically induced fiber grating. Theoretical analysis shows that gap mode can be effectively generated on the surface of the Ag-NPs-coated fiber probe excited via an AVB. The experimental result shows that the intensity of Raman signal obtained with analyte molecules of malachite green by exciting the Ag-NPs-coated fiber probe via an AVB is approximately eight times as strong as that via the linear polarization beam(LPB), and the activity of the AVB-excited fiber probe can reach 10^-11 mol∕L, which cannot be achieved by LPB excitation.Moreover, the time stability and reliability are also examined, respectively.展开更多
基金National Natural Science Foundation of China(NSFC)(61675169,61675171,11634010)National Key R&D Program of China(2017YFA0303800)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(2018JM6036)Shaanxi Provincial Key R&D Program(2018KW-009)
文摘The synergy of a plasmonic tip and fiber-based structure light field excitation can provide a powerful tool for Raman examination. Here, we present a method of Raman spectrum enhancement with an Ag-nanoparticles(Ag-NPs)-coated fiber probe internally excited via an azimuthal vector beam(AVB), which is directly generated in a few-mode fiber by using an acoustically induced fiber grating. Theoretical analysis shows that gap mode can be effectively generated on the surface of the Ag-NPs-coated fiber probe excited via an AVB. The experimental result shows that the intensity of Raman signal obtained with analyte molecules of malachite green by exciting the Ag-NPs-coated fiber probe via an AVB is approximately eight times as strong as that via the linear polarization beam(LPB), and the activity of the AVB-excited fiber probe can reach 10^-11 mol∕L, which cannot be achieved by LPB excitation.Moreover, the time stability and reliability are also examined, respectively.
