Research And Design Of Laser Line Shaped Top-hat Shaping System

Laser as a tool,has been widely used in materials processing?medical applications?laser display and so on.The demand for beam shape and spatial intensity distribution vary from application to application,examples such as the ploy-si thin-film transistors'green laser annealing?insulated gate bipolar transistors'backside laser annealing?laser polishing and laser cleaning,laser beam with line shaped top-hat is desired.The typical laser beam intensity is Gaussian beam,therefor Gaussian beam shaping is required.Beam shaping system mainly included refractor and integrator.In this paper,the first of all,theoretical models of flattened beam are discussed and researchs the propagation characteristics in free space.In the same,flattened beams'M~2are deduced and studys the relationship between M~2 and shape factor;matching factor is introduced to associate the different flattened beam models together to achieve an equivalent transformation.The next,as for the single lens refractive aspheric beam shaping system,surface profiles equations are deduced in detail by simple method.Studying surface profiles equations deeply,pointing out its singular radius and surface boundary constrains.Zemax macro language is used to design single lens refractive aspheric shaper and tolerance analysis of shaping system is made.In addition,the performance of shaping system under different working condition is studied,line shaped top-hat is achieved by dealing with uniform beam.Finally,puting forward cutting and rearranging beam shaping system based on integrator,cylindrical lens are used to expand beam in one dimension,cutting and rearranging is achieved by two groups of parallel plates and using cylindrical lens to focus the rearrangement beam.In the focal plane,line shaped top-hat is obtained,the size is 1mm×0.06mm and uniformity is 93%by Zemax simulation.Experiment is designed to validate the feasibility and come up with improment method according exist issue.