High-speed surface functionalization by direct laser interference patterning (Conference Presentation)

Abstract

The material processing by two or more interfering laser beams, is referred to as Direct Laser Interference Patterning (DLIP). The periodic intensity pattern of the overlapping laser beams is used to ablate or modify the material so a functionalization of the surface is achieved. By adjusting the number, direction, intensity and polarization of the interfering beams, the detailed geometry of the intensity pattern can be shaped and the realizable feature sizes can be continuously adjusted within the micro- and submicrometer range. Consequently, the surface texture can be engineered and tailored to perfectly suit the needs of a given application. Typical applications of DLIP range from in- and out coupling of light in solar cells or organic LEDs over improvement of tribological properties in engine parts to security markings and decoration applications due to the shimmering effect of the periodic textures. On laboratory scale, an improvement over unprocessed surfaces has been demonstrated in all of these mentioned applications. However, so far the feed rates have not sufficed to allow an industrial application of the technology. Now, in a joint project of laser manufacturer, optics designer and engineering company, a machine platform has been developed which allows high surface processing speeds in an industrial environment. Feed rates in the range of square meters per minute (corresponding to about one billion features per second) can be achieved. With the help of this platform, DLIP can finally be lifted to industrial application.