Surface-enhanced Raman scattering in femtosecond laser-nanostructured Ag substrate

Abstract

We demonstrate that a surface-enhanced Raman scattering (SERS) substrate could be directly fabricated on the surface of Ag film by femtosecond laser micromachining. According to the morphology observation by SEM, an amount of nanoparticles, nanoprotrusions, and nanospikes were found to form in the ablation region and the density and size distribution of these Ag nanoparticles depended possibly on the incident laser intensity. Additionally, a large area of nanostructured region was produced by fast line scanning, and an enhancement factor of ∼105 was obtained in this region after the sample was soaked in the rhodamine 6G solution for 30 min.