Large-Beam Picosecond Interference Patterning Of Metallic Substrates

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm(2)/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 mu m periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164 degrees, 156 degrees, and 150 degrees in the case of stainless steel, invar, and tungsten, respectively.