This is a process using a femto-second laser, which produces nanostructures with high surface area on metals such as Ti, Pt, Au, Cu, Al, W. The method can dramatically alter the surface reflectivity rendering the metals black, or can be controlled to produce unexpected colors. For example, platinum and aluminum can be made to appear gold, gray, or black.
The method for modifying the surface of metals and other materials with femto-second laser pulses can be used in several applications.
For increasing optical absorption of metals for light absorbers in detectors and sensors (from UV to terahetz), for low reflectance black surfaces in optical system hardware, and for making marks and images on metal. Periodic structured surfaces on metals can produce spectral reflection to colorize the metal. Polarization-dependent spectral reflection can make different colors at different viewing angles. The process can also produce nano-structured surface on metals to increase surface area for catalysis and to induce bio-medical compatibility for bone and dental implants.
The precise control of the femto-second laser enables the creation of these various micro- and nano-scale structures on metals and other materials. The process for preparation of these nanostructures is simple, clean, rapid and dry, and does not involve hazardous chemicals. It can produce such surfaces in both large areas, through a scanning laser beam, and in small micron size areas, limited to the focal spot diameter of the laser beam. It creates large surface-to-volume ratios on surfaces of metals that have potential applications in medical implants or to promote catalysis. The structures and color are intrinsic to the metal. No coatings are involved. Precise control of the structures and marks is possible at micron scale. Image-wise marking is possible in an interesting, if limited, palette of colors.
URV Reference Number: 2-11150-07004