Affiliation:
1. Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China
2. State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Engineering Zhejiang University Hangzhou 310027 China
3. School of Optical and Electronic Information Huazhong University of Science and Technology & National Engineering Research Center for Laser Processing Wuhan 430074 China
Abstract
Laser‐induced periodic surface structure (LIPSS) can form structural color on the metal surfaces with high production efficiency and thermal stability, and has been used in various industrial applications such as unfaded color marking and anti‐counterfeiting. Herein, a novel fabrication scheme of multilayer LIPSS is proposed by multiple writing in situ with changing the laser polarization direction, to exhibit an effect of color superposition. To verify this approach, the color formation mechanism of LIPSS on the stainless‐steel surface is analyzed by finite‐element numerical calculation and reveals that the high‐angular dispersion of LIPSS is mainly the result of optical diffraction occurring on the surface of periodic structures. The relationship between the angular dispersion of multilayer LIPSS and laser‐processing parameters is established. Through the proposed multilayer LIPSS coloring technology, vivid full‐color patterns on the steel surface are demonstrated, and the in situ superposition of three‐layer graphs is realized, which can greatly enrich the color levels and be competitive in industrial applications.
Subject
Pharmacology (medical),Complementary and alternative medicine,Pharmaceutical Science