High‐Brightness, Wide‐Gamut, and High‐Resolution Structural Colors via Ultrafast Laser Oxidation of Ti/TiO ₂ Films

The scalable fabrication of high-brightness, wide-gamut, and high-resolution structural colors remains challenging due to the reliance on complex nanofabrication or coating techniques. Here, we demonstrate a facile and flexible approach to generating vivid structural colors via ultrafast laser processing of Ti-TiO₂-Ti sandwich-structured thin films. The multilayer design enables controlled oxidation with oxide thicknesses exceeding 200 nm under laser irradiation. Optical characterization reveals dual absorption enhancement peaks and a reflection enhancement peak in the visible spectrum. By tuning the accumulated laser fluence, we modulate the oxidation state of Ti and the optical properties of TiO₂, achieving vibrant structural colors with high reflectivity and a color gamut exceeding 80% sRGB. Peak reflectance reaches 60%, and the highest color difference (ΔE) control precision is less than 3. Moreover, a resolution up to 30 000 DPI is attained. The laser-induced structural colors exhibit excellent durability, passing standard tests for thermal stability and corrosion. This method enables direct patterning of high-luminance colors and holds promise for applications in art, anti-counterfeiting, signage, and flexible photonic devices.