Investigation of computer-generated diffractive beam shapers for flattening of single-modal CO_2 laser beams

A full cycle was realized of the photolithographic development and detailed testing of a diffractive optical element that transforms the diverging Gaussian beams of CO(2) lasers into a uniformly filled-in rectangle. The zone feature size of the beam shaper, the diffractive efficiency and accuracy, the focus depth, and the stability with respect to the size and the divergence of incident Gaussian beams are studied by computer modeling. Calculated flattop intensity distributions are presented in the same form of gray-level pictures and three-dimensional plots as the corresponding results measured by an IR camera.