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

ABSTRACT 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‐ () and sub‐wavelength (/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.