Hyperbolic phase function used in a spatial light modulator for flat top focus generation

We report on a novel transversal beam shaping approach to convert a Gaussian beam to a flat top focus profile by employing a hyperbolic phase function in a liquid crystal on silicon (LCOS) spatial light modulator (SLM). The well-known Powell lens approach is compared to ours. The analytically obtained phase function for the flat top focus conversion problem is compared to our approach theoretically and experimentally. A strategy for the generation of squared and circular top hat foci is derived.