Fig. 1. (a) Schematic of tapered fiber preparation; (b) schematic of tapered fiber SERS probe structure (insets show the optical characterization and SEM images)

Fig. 2. Experiment setup of tapered fiber SERS probe

Fig. 3. SEM images of silver nanoparticles deposited on the tapered end face of probe under the conditions of hot water bath and different deposition periods. (a) 30 s; (b) 60 s; (c) 90 s; (d) 120 s

Fig. 4. SEM images of silver nanoparticles deposited on the tapered end face of probe under the conditions of room temperature and different deposition periods. (a) 120 s; (b) 180 s; (c) 240 s

Fig. 5. SEM images of silver nanoparticles deposited on the tapered end face of sample probe at AgNO3 solution with different concentrations. (a) 0.01 mol/L; (b) 0.05 mol/L; (c) 0.1 mol/L

Fig. 6. Raman spectra of ten samples immersed in R6G solution with concentration of 10-9 mol/L

Fig. 7. Fluorescence signal of R6G solution with concentration of 10-9 mol/L

Fig. 8. Schematic of silver nanoparticles on the end face of fiber. (a) Schematic of the structure; (b) simulation model

Fig. 9. Local electric field enhancement of silver nanoparticles (color bars represent electric field intensity, its unit is V·m-1)