Fabrication of Micro/Nano Multiscale Structures on Aluminum Alloy With Control of Laser-Induced Periodic Surface Structure

Abstract Recent advances in micro/nanofabrication techniques enable the creation of surface structures that confer materials with enhanced mechanical, optical, and surface energy functionalities. A prominent technique, laser-induced periodic surface structure (LIPSS), leverages ultrashort pulsed laser irradiation to produce periodic nanoscale patterns on material surfaces. This process is driven by surface plasmon excitation and subsequent electric field enhancement, leading to selective material ablation. However, achieving consistent LIPSS across varying crystal orientations—especially in materials like stainless steel and aluminum alloys—remains challenging due to the intricate relationship between electron density variations and crystal structure. In this study, a new method combines ultrashort pulsed laser irradiation with pre-patterned microgrooves, facilitating precise, controllable, and reproducible LIPSS formation. By examining electric field distributions post-irradiation, an optimal pre-pattern geometry was identified, allowing effective control of LIPSS characteristics, such as linearity, height, and periodicity. Microgroove geometries, including sine wave and cross-hatch patterns, enhance LIPSS uniformity and enable complex surface structures. This study underscores the potential of microgroove pre-patterning as a strategy for controlling LIPSS and achieving multiscale structures with improved functionalities including hydrophobicity, thereby advancing the practical applications of micro/nanostructured surfaces in material science.