In order to break the limitation that the gap is fixed once it was synthesized for traditional flexible surface-enhanced Raman scattering substrate, in this work, a laser-induced reduction method was used to fabricate ordered silver nanodot arrays on flexible substrates. By using rhodamine 6G as a probe molecule, Raman characterization is carried out on the hydrogel film/silver substrate at expanded and shrunken states. The substrate shows great reproducibility, and the average relative standard deviation of the probe is 8.7%. In addition, when the hydrogel film was shrunk by 75%, the intensity at 1650 cm−1 will be enhanced by about 36 times, and the detection concentration of the R6G molecule can reach 10−7 mol/l.
