Femtosecond laser patterning based on the control of surface reflectance

Abstract

In this study, we present a femtosecond laser patterning method based on the control of surface reflectance. This laser patterning method is based on the laser-induced periodic surface structure (LIPSS), and we first studied how the LIPSS pattern evolves and the corresponding surface reflectance changes as process parameters are varied in a large process window. It was found that the reflectance of stainless steel can be changed from 66% to 5%, and by choosing the proper parameters, elegant patterns can be fabricated. Using the method, a multi-faceted ball was successfully fabricated by employing 22 surface reflectance values. The mechanism behind the reflectance change and the effect of the shield gas on the surface morphology and patterning quality were also investigated.