| 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 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 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. |
| 主权项 |
1. A method of modifying a medium so that a grayscale image is obtainable from the medium, the method comprising:
providing a medium having a surface; scanning a laser beam relative to the surface, the laser beam comprising a plurality of optical pulses having a pulse width less than about 100 picoseconds, the laser beam delivering optical energy to the surface of the medium; and varying the optical energy delivered to different regions of the surface of the medium, thereby altering at least one of reflectivity, absorptivity, or diffractive properties of the regions to provide the grayscale image obtainable from the medium, wherein at least a portion of said plurality of pulses of said laser beam are generated at a repetition rate greater than 100 kHz and focused into focal spots having focal spot diameters, wherein at said repetition rate greater than 100 kHz accumulation of overlapping pulses within said medium and over said focal spot diameters results in improved contrast in said greyscale image while forming an image portion in a shorter time relative to contrast at time obtainable at a repetition rate less than 100 kHz. |
