Large-area surface-enhanced Raman scattering-active substrates fabricated by femtosecond laser ablation

A rapid and simple approach to fabricate large-area surface-enhanced Raman scattering-active (SERS-active) substrates is reported. The substrates are fabricated by using femtosecond laser (fs-laser) direct writing on Silicon wafers, followed by thin-film coating of metal such as gold. The substrates are demonstrated to exhibit signal homogeneity and good enhancement ability for SERS. The maximum enhancement factor (EF) up to 3×107 of such SERS substrates for rhodamine 6G (R6G) at 785 nm excitation wavelength was measured. This technique could demonstrate a functional microchip with SERS capability of signal homogeneity, high sensitivity and chemical stability.