Extending ultra-short pulse laser texturing over large area

Here we show for the first time that with relatively low fluence it is possible over stainless steel, to obtain surface texturing by utilising a 2 MHz femtosecond laser jointly with a polygonal scanner head in a relatively low fluence regime (0.11 J cm−2). Different surface textures (Ripples, micro grooves and spikes) can be obtained varying the scan speed from 90 m s−1 to 25 m s−1. In particular, spikes formation process has been shown and optimised at 25 m s−1 and a full morphology characterization by SEM has been carried out. Reflectance measurements with integrating sphere are presented to compare reference surface with high scan rate textures. In the best case we show a black surface with reflectance value < 5%.