Fig. 1. Schematic of experimental process

Fig. 2. XRD patterns of Ag, Cu,and Al thin films before and after laser irradiation

Fig. 3. AFM images of Ag, Cu, and Al thin films before and after laser irradiation

Fig. 4. RMS surface roughness of Ag, Cu, and Al thin films as a function of laser scanning speed before and after laser irradiation

Fig. 5. Absorption spectra of Ag, Cu, and Al thin films before and after laser irradiation. (a) Absorption spectra of Ag, Cu, and Al thin films before laser irradiation; (b) absorption spectra of Ag thin film at different scanning speeds after laser irradiation; (c) absorption spectra of Cu thin film at different scanning speeds after laser irradiation; (d) absorption spectra of Al film at different scanning speeds after laser irradiation

Fig. 6. SERS spectra of Ag, Cu,and Al thin films before and after laser irradiation

Fig. 7. Electric-field intensities of Ag, Cu, and Al thin films before and after laser irradiation obtained from FDTD simulations