The comparison of fabricating colorful patterns on stainless steel with femtosecond and nanosecond laser pulses

The colorful patterns are produced on stainless steel by irradiating with scanning femtosecond and nanosecond laser pulses. The SEM images show that the surface of the colorful patterns fabricated by femtosecond laser pulses are covered with laser-induced periodic surface structures (NC-LIPSS), and the surface structures have characteristics that are similar to gratings, which can exhibit enhanced colors in ambient white light. However, the colorful patterns fabricated by nanosecond laser pulses only have more floccus structures are generated, and only appear golden yellow in different degree. The reflectance analysis demonstrates the total reflectance of patterns fabricated by femtosecond laser pulses is greater than that of being fabricated by nanosecond laser pulses in the UV, Visible, and IR regions.