High-speed Laser-Induced Periodic Surface Structures (LIPSS) generation on stainless steel surface using a nanosecond pulsed laser

Laser Induced Periodic Surface Structures (LIPSS) can be reliably produced using ultra-short laser pulses from 10 fs up to 10 ps, though it is a very time-consuming process. As the processing speed scales with the average power, the use of nanosecond-pulsed lasers can be cost-effective and reduce processing time, especially for industry requirements of treating large surface areas. In this work, we studied the influence of irradiation parameters and surface finishing in LIPPS efficient generation using a 100 ns nanosecond pulsed laser on AISI 304 stainless steel. Diffracted light intensity was used to evaluate the LIPSS quality and homogeneity in large surface areas, allowing the determination of process parameters interval for different initial surface roughness in a simple and fast way. The most efficient and uniform LIPSS were generated at 49 nm initial surface roughness, with single spot fluences varying from 3 J/cm2 to 4 J/cm2 and 83% beam overlapping, with only one or two successive scans. Processing speed as high as 50 mm2/s was obtained with a single scan at the maximum single spot fluence tested (4 J/cm2), showing the potential use of nanosecond pulse lasers in industrial practical applications.