Probe-Beam Deflection Diagnostic of Shock Waves Generated during Direct Laser Interference Patterning

Laser-based technologies have become a relevant method for creating microstructured surfaces on materials for enhancing their functionalities. In this field, traditional monitoring methods can be supplemented by analyzing acoustic emissions (AE), offering insights into laser-material interactions for quality control. This study explores the dynamics of laser-induced shock waves and plasma from stainless steel targets under atmospheric conditions using Direct Laser Interference Patterning (DLIP) as well as Direct Laser Writing (DLW). Utilizing optical beam deflection technique, the propagation of a supersonic shock wave and its evolution into an acoustic wave could be measured, alongside the plasma plume. Acoustic emissions from the laser ablation were recorded at various distances, with the explosion blast wave model providing a good estimation of the shock front’s temporal development. These emissions originate from the ablation plasma’s lifecycle, including expansion, oscillation, and contraction. The performed research enhances the understanding of DLIP and DLW, suggesting new pathways for improved monitoring and control in laser surface patterning.