Defect-Assisted Ultra-Regular LIPSS for Multi-Level Structural Coloring

Laser-induced periodic surface structures (LIPSS) offer high-throughput route for creating regular nanotextures over diverse materials. However, achieving large-scale ultra-regular LIPSS with tailored periodicity on common materials with non-ideal interfaces, as polished metallic surfaces, remains challenging. Here, we demonstrate defect-engineering approach to produce self-organized gratings over polished AISI304 steel surface with exceptional dispersion of LIPSS orientation angles < 1° and diffraction efficiency above 15% – among the highest values ever reported for all LIPSS types. This is achieved by IR femtosecond-laser pre-patterning the surface with isolated nano-grooves, which control excitation and scattering of surface waves to guide LIPSS formation along predefined trajectory. We employ an original Fourier-plane micro-imaging technique enabling highly sensitive and localized assessment of exceptional LIPSS regularity through light diffraction, with the data rapidly averaged over square-centimeter areas. Using defect-assisted patterning we demonstrate both near- ((Formula presented.)) and sub-wavelength ((Formula presented.) /2) LIPSS with high regularity. Finally, we highlight the practical value of our approach demonstrating multi-level structural coloring by tuning LIPSS periodicity through the angular defect-assisted recording and controlling local diffraction efficiency by laser post-treatment. Our results provide practical pathways for large-scale production of tunable and ultra-regular LIPSS over commercial materials, with immediate applications in nanophotonics, sensing, and optical instrumentation.