Nanometric Surficial Reflectors: Achieving High-Performance and High-Throughput Structural Coloration Through Modulation-Assisted Machining.

Structural coloration, which generates color through physical structures, has broad applications but often faces challenges in achieving high color performance while being scalable for mass production. In this study, a novel single-layer wavelength-selective reflector capable of producing a broad color gamut with local angle independence is introduced, fabricated using a modulation-assisted ultra-precision machining process. The structure features multi-level submicron steps that sequentially filter light of different wavelengths, overcoming the limitations of conventional periodic structures that suffer from narrow color gamut and angle-dependent color shifts. This approach integrates a purely mechanical machining process, shaping reflectors in a single step using a precisely controlled modulation trajectory. This enables efficient, scalable fabrication while preserving the desired structural characteristics at the nanoscale. Color performance comparable to the sRGB space is demonstrated and full-color images are successfully rendered on metallic surfaces. The proposed reflector design provides a new pathway to scalable production of vibrant, angle-independent structural colors with potential applications in anti-counterfeiting, data storage, and high-quality coloration.