Controlling Micron and Submicron Scale Laser Induced Surface Structures on Stainless Steel with Industrial Femtosecond Lasers

Generation of laser induced surface structures has been reported as an effective way to function-alize the surface of a solid material. Structure size, symmetry and hierarchical length scale formation has a significant influence on the material's macroscopic properties. The feasibility to produce surface morphologies at different scales is on high demand since they can be employed to mimic bio inspired morphologies in order to enable a variety of unexplored surface functionalities such as bactericidal, anti-icing and anti-reflective surfaces. In the present paper, we report on a comprehensive study dealing with laser induced surface structures morphology control, in terms of symmetry and size, utilizing a high throughput industrial femtosecond source with pulse duration of 350 fs. Interestingly, structures at the micron scale can be effectively tuned via fluence manipulation meanwhile tuning structures at the submicron scale requires double pulse irradiation with polarization modification. For double pulse irradiation the effect of polarization, fluence and overlap was investigated for interpulse delays up to 4 ns. We find out that a large variety of surface structures can be achieved by this way. We believe that our work provides novel data on surface texturing and pushes forward the level of technological readiness of laser surface functionalization.