Gaussian Beam Shaping Based On Aspheric Cylindrical Lens

Laserhas been widely applied in many new and high-tech fields of laser wielding,surface heat treatment, pattern recognition, laser materials processing, lithography and so on,which requires specific optical system to convert a Gaussian beam to a flat-top distributionand rectangle beam. Therefore, in order to improve the application levels of laser technologyand meet the demands of different occasions, it is necessary to develop an essential beamshaper.The transformation from a Gaussian beam into a flat-top distribution and rectangle beamalways requires specific Gaussian beam shaping system. Compared with other beam shapingmethod, Refractive shaper can works better with less energy loss.At the same time, it is moresimple, reliable and practical.In this article, we propose and demonstrate an aspheric cylindrical optical Gaussianbeam shaping system, which is composed of a plane-convex cylindrical lens and aplane-concave cylindrical lens placed in orthogonal position.Firstly, axisymmetric beam shaping system are introduced, including the basic theory ofnonimaging optics, feature of Gaussian beam and flat-top beam, numerical calculatingmethod of aspheric lens and ZEMAX optical design software. Based on above, we present anon-axisymmetric Gaussian beam shaping system. The principle of Gaussian beam shapingsystem based on aspheric cylindrical is studied theoretically, and the ray-tracing function ofan arbitrary rays between an incident plane and an image plane is deduced in detail. Then, adesign example of beam shaping system is shown. ZEMAX programming language is used tocompile optimization function, the real ray tracing method is adopted to design and optimizethe shaping system automatically. By using the shaping system, the accurate transformation ofinput beam with a Gaussian beam parameters in terms of Wavelength632.8nm and waistradius5mm into target beam with rectangle dimension of100mm×3000mm and uniformirradiance distribution is realized at the distance of5000mm. Simulation results illustrate thatthe uniformity of beam is higher than95%and the energy loss is less than10%.Finally, the surface profile errors of aspheric cylindrical lens are analyzed by MATLABand Assembly errors of optical elements are analyzed by ZEMAX, which is leading to atolerance of beam shaping system.