Innovative method to enhance the control over the fabrication of LIPSS on metallic surfaces

Gomez-Aranzadi, Mikel; Casquero, Noemi; Martinez-Caldero, Miguel; San-Blas, Alejandro; Olaizola, Santiago Miguel; Rodriguez, Ainara

LIPSS are an emergent method of fabricating functional surfaces. A high repetition rate ultrashort pulsed laser was used to generate LIPSS on metallic surfaces. Different combinations of the processing parameters were tested to study their effect on the period of the LIPSS. Additionally, the influence of the repetition rate (laser frequency) on the LIPSS period was also studied when the same number of pulses, polarization and peak fluences are applied. Finally, a chemical analysis was performed in order to establish a correlation between the laser processing conditions and the resulting chemical modifications (especially oxidation) in the ultrashort pulse regime. As expected, the analysis shows a decrease in the period of the LIPSS as the number of pulses increases, while the other processing parameters affect the period slightly. Regarding the laser frequency, variations in the repetition rate –while the rest of the parameters are kept constant- only slightly affect the period and morphology of the LIPSS.  In the case of the chemical variations, two different regimes were found, with Low Spatial Frequency LIPSS exhibiting no oxidation for low accumulated fluences and High Spatial Frequency LIPSS presenting increased oxidation as the fluences accumulate.

Proceedings of Lasers in Manufacturing 2019