Diffractive optic elements for forming scanning beams

A novel approach for designing quasi non-diffracting beams is presented. When using these beams for scanning images, the resulting signals have low contrast levels that are maintained over distances far exceeding depth-of-focus distances obtainable with Gaussian beams. A system using two phase-only diffractive optics filters separated by a free space region is sufficient to generate such beams. Gerchberg Saxton algorithms are applied for determining the phase functions necessary for transforming the input laser beam into the desired beam distribution. The characteristics of the beams are presented.