Non‐Continuous Iridescent Variable Structural Color Based on Metallic Surface Periodic Structures

ABSTRACT Optically variable colors demonstrate significant potential in the fields of decoration and anti‐counterfeiting, yet current technologies still face a variety of challenges. Ink‐based methods raise environmental concerns and lack durability, while ink‐free techniques such as laser marking suffer from low processing efficiency and almost all of them are limited to continuous iridescent colors generated by grating diffraction. Here, we fabricated a periodic arched microstructure on the titanium surface by precisely controlling the line spacing parameter, achieving a non‐continuous iridescent and strongly direction‐dependent dual‐color conversion effect. Under relatively low energy density, material ablation is minimal, and due to oxygen infusion during oxidation, the laser‐scanned area experiences bulging. Under specific line spacing conditions, the centers and edges of adjacent scan tracks overlap, forming arched structures in the overlapping regions. The ridge and side flanks of these structures exhibit different oxide film thicknesses, enabling them to selectively reflect light of different wavelengths at varying reflection angles in space, thereby producing a color‐shifting effect as the viewing angle changes. This technology overcomes traditional limitations by combining environmental sustainability, high processing efficiency, and excellent durability, offering an innovative solution for advanced optical applications.