Fig. 1. Apparatus for inducing the deposition process

Fig. 2. Morphologies of gold nanorods
(a): SEM image; (b): TEM image of

Fig. 3. Length and diameter of gold nanorods

Fig. 4. SERS experimental device of fiber optic probe

Fig. 5. Schematic diagram of laser induction process

Fig. 6. SEM image of the end surfaces of laser induced fiber probes
(a), (b) and (c): The end surfaces of laser fiber fabricated by laser induction in gold nanorod solutions with concentrations of 1.5×10^-9, 1.0×10^-9, 7.5×10^-10 mol·L^-1 respectively; (d), (e) and (f): The details of (a), (b) and (c) respectively; (g): The enlarged SEM image of (e); (h): The enlarged SEM image of (f)

Fig. 7. (a) SERS spectra measured using the optical fiber probes fabricated by laser induced deposition in the gold nanovods solutions with the concentrations of 1.5×10^-9, 1.0×10^-9 and 7.5×10^-10 mol·L^-1; (b) SERS spectra after baseline removal
The concentration of 4-ATP is 1×10^-6 mol·L^-1

Fig. 8. SERS intensity of peak at 1 079.971 cm^-1 using the probes fabricated in the gold nanorods solutions with concentrations of 1.5×10^-9, 1.0×10^-9 and 7.5×10^-10 mol·L^-1
Colours correspending to various concentration are the same as in Fig.7

Fig. 9. (a) The electric field intensity distribution of a single gold nanorod; (b) and (c) The electric field intensity distributions of two gold nanorods arranged at any Angle; (d), (e) and (f) The electric field intensity distributions of two gold nanorods side by side

Fig. 10. (a)Raman spectrum of 4-ATP measured again by optical fiber SERS probe prepared in gold nanorod solution with concentration of 7.5×10^-10 mol·L^-1 after 15 days; (b) Raman spectrum of 4-ATP measured by SERS probe prepared in 7.5×10^-10 mol·L^-1 gold nanorod solution