Fig. 1. Schematic setup for the fabrication nd spectroscopic measurement

Fig. 2. "Phase transition" characteristics of the microstructure of gold nanoparticles. (a) SEM image of the spin-coated sample with a colloidal concentration of 100 mg/mL before irradiated by laser pulses; SEM images of samples prepared by different concentrations of gold nanoparticle solution irradiated by laser pulses for 16 min, (b) 40 mg/mL, (c) 70 mg/mL, and (d) 100 mg/mL

Fig. 3. Extinction spectra. (a) Extinction spectra of the gold nanoparticles at different irradiation time with femtosecond laser pulses; (b) extinction spectra of the gold nanoparticles with colloidal concentrations of 40, 70, and 100 mg/mL, respectively, irradiated by laser pulses for 16 min

Fig. 4. Multi-peak fitting for the extinction spectra of the gold nanoparticles after phase transition using three-peak Gaussian function