Scanner-Based Direct Laser Interference Patterning on Stainless Steel

Direct laser interference patterning (DLIP) so far has been used almost exclusively in combination with mechanical translation stages reaching impressive throughputs for very specific configurations. As an alternative, DLIP modules can be combined with laser scanners, however presenting some limitations in comparison with standard static optical setups due to the limited possible spatial separation between the interfering beams. Herein, the fabrication of periodic microstructures on stainless steel using a galvanometer-scanner DLIP approach is addressed. Line-like patterns with spatial periods ranging from 2.9 to 12.8 mu m are produced using a nanosecond pulsed laser source operating at a wavelength of 527 nm. The scan fields generated are evaluated with respect to the structure quality and scan field size, with dependence on the spatial period. Furthermore, the correlation between the spatial period, laser fluence, total number of pulses, and resulting structure depth of the line-like patterns is discussed. In addition, the optimization of process parameters leads to surface patterns with aspect ratios greater than 1. The achievable structuring speeds are determined under consideration of the used number of pulses. Finally, throughputs up to 7.69 cm(2) min(-1) with less than 0.5 W laser power at a repetition rate of 3.5 kHz are realized.

Automated summary

This study addresses the fabrication of periodic microstructures on stainless steel using a galvanometer-scanner DLIP approach, evaluating the relationship between structure quality, scan field size, and spatial period of line-like patterns. Optimization of process parameters leads to surface patterns with aspect ratios greater than 1, achieving structuring speeds up to 7.69 cm(2) min(-1) with less than 0.5 W laser power at a repetition rate of 3.5 kHz.