Uniform Intensity Distribution

Most  of the laser types used produce output beams with circular or  elliptical cross-section, which have Gaussian or near Gaussian intensity  distribution. This Gaussian intensity distribution is acceptable, and  is usually beneficial for many applications of laser focusing on a small  spot. However, for many different uses,  uniform intensity distribution  (often referred to as a "flat top") would be more important. 

For  example, in the material processing task, the uniform intensity  distribution can ensure the uniform processing of the whole laser  illumination area. It is also valuable when the laser is mainly used for  illumination. This is because uniform illumination makes the same  features appear to have the same brightness, regardless of where they  are located in the illumination field, thus simplifying the image  processing task and improving the contrast and resolution. These same  advantages apply to a wide range of other applications and can be  broadly classified as "lighting" from machine vision through flow  cytometry, inspection, and even some medical uses.