Micro-lens arrays for laser beam homogenization and transformation

摘要

For many innovative applications a significant improvement in the homogeneity of the laser beam is a critical requirement when using semiconductor lasers. There are several different methods for the homogenization of laser radiation. Homogenization using micro-cylinder lens arrays is a considerably elegant and compact solution. In this case the incident laser beam is separated into partial beams by one or more micro-lens arrays. These partial beams are then overlaid in the homogenization plane by the downstream optics. Depending on the arrangement and geometry of the micro-lenses, this enables homogeneously illuminated lines, rectangles or squares to be generated. The major advantage of this solution lies in the increased freedom of adjustment to account for the initial beam profile, as well as the extremely compact design. In addition to a comparison of different homogenization principles the paper describes new approaches of homogenization via micro-lens arrays and compares the impact on the array performance by different manufacturing approaches.