The Researchand Design Of The System That Converting A Gaussian To A Flattop Beam

Laser has been widely applied inn the field of Laser holography, laser materials manufacture, and laser medical treatment,. The reshaping system converting Gaussian beam to flattop beam by making use of laser beam reshaping equipment could satisfy the production needs.Among the reshaping systems converting a Gaussian beam to a flattop beam, the system composed of two plane-convex aspheric lenses or one plane-concave and one plane-convex aspheric lens, is a relatively simple structure for its compactness, sound effects in beam reshaping, and simplicity in manufacture. And in actual production processing, the asphericity and surface roughness of aspheric mirror are the crucial factors.In this article, at first we calculated the influence of related characteristic parameters on flattop beam, and analyzed transmission of various flattop beams, as well as parameters which decide irradiance distribution of flattop beam. At the same time, we presented the method of numerical computation of two aspheric lenses, and obtained numerical relationship between asphericity and characteristic parameters of Kepler aspheric lens and Galileo aspheric lens. We inferred how to fit the special curve in conformity to the expressions in some optical software such as ZEMAX besides numerical calculation with theoretical analysis, and gave the algorithm based on MATLAB. In the meanwhile, we have attempted to reduce the order of expressions of aspheric mirrors, compared fitting error of aspheric mirrors in various order of expressions, and achieved a series of aspheric lens data meeting the requirements of processing.For a pairs of aspheric lenses worked out previously could merely reshape the Gaussian beam with particular waist radius, and that flattop beam could not go far remaining well-distributed, we designed two sets of new laser beam reshaping systems, which are able to convert a Gaussian beam with waist radius of any within a certain range to a flattop beam. Subsequently, the system got been passed in physical optical propagation in ZEMAX.Finally, on the base of combined analysis of ZEMAX and theoretical formula, we made a comparison between one system aligned with two expanders and the other one without above-mentioned devices, analyzed influence on uniformity of the output irradiance distribution with variation of parameters of Gaussian beam and expanders, and attained an ideal result through summarizing foregoing work.