A light beam with non-uniform cross-sectional intensity profile is positioned into a central portion and two side lobes and the two side lobes are folded over the central portion to form a concentrated beam at a focus plane having substantially uniform intensity profile. The partitioning and folding...http://www.google.com.au/patents/US4793694?utm_source=gb-gplus-sharePatent US4793694 - Method and apparatus for laser beam homogenization
