Efficient surface processing of high surface quality with two-color double-pulse femtosecond laser ablation

We investigate the femtosecond laser ablation of 304 stainless steel (AISI 304), aiming to achieve a high ablation rate, while maintaining low surface roughness. We observe that the surface ablation with 1030 nm-wavelength laser pulses shows a higher ablation rate than that with the 515 nm-wavelength pulses, whereas the surface roughness obtained with the 1030 nm pulses is significantly higher as compared to that obtained with the ablation of 515 nm pulses. We also show that by the use of the two-color double-pulses at 1030 and 515 nm wavelengths, a much higher ablation rate has been achieved with a surface roughness comparable to that obtained with the ablation of 515 nm pulses.