ULTRASHORT LASER MICRO-TEXTURE PRINTING

摘要

Systems and methods for providing laser texturing of solid substrates are disclosed. The texturing may be used to provide grayscale images obtainable from substrates, which may include steel, aluminum, glass, and silicon. In some embodiments, images may be obtainable from the substrate by modifying the reflective, diffractive, and/or absorptive features of the substrate or the substrate surface by forming random, periodic, and/or semi-periodic micro-structure features on the substrate (or substrate surface) by an ultrafast laser pulse train. The micro-structure features may have average sizes slightly larger, comparable to, and/or smaller than the wavelength of light of the ultrafast pulse train. The ultrafast pulse train may be modulated in order to vary, for example, optical exposure time, pulse train intensity, laser polarization, laser wavelength, or a combination of the aforementioned. The micro-structure features may be modified by controlling the environment near the substrate (e.g., the atmosphere, which may include reactive chemical species in some embodiments). In some embodiments, the micro-structure may be fixed for long-term preservation using enamel and/or polymer or other overcoats. The ultrafast pulse train and the substrate may be scanned with respect to each other to provide different optical energies to different regions of the substrate (or substrate surface). In some embodiments, the image is provided by making one or more passes of the ultrafast laser pulse train relative to the substrate.