Modification of surface properties of solids by femtosecond LIPSS writing: comparative studies on silicon and stainless steel

摘要

We investigate the implication of modified surface morphology on wettability of stainless steel (AISI 304) and silicon (100) targets covered by laser-induced periodic surface structures (LIPSS) on extended areas (10×10 mm~2). Using multiple pulses from a Ti: Sapphire laser (790 nm/100 fs/1 kHz) at a fluence in the range of 0.35-2.1 J/cm~2 on a spot of 1.13 × 10~(-4) cm~2, we scanned the target under the spot to cover a large area. A systematical variation of the irradiation dose by changing the scanning speed and thus dwelling time per spot results in the formation of surface patterns ranging from very regular linear structures with a lateral period of about 500-600 nm to complex patterns of 3D microstructures with several-urn feature size, hierarchically covered by nano-ripples.