Optimization Design Method For Microlens Array Laser Beam Shaping Devices Based On Optics Non-imaging

In lithography, laser printing, materials processing, medical equipment, opticaldata storage, optical processing, electronics industry of the fine processing,holographic interferometry, optical holography and other fields, laser shaping systemis one of the key factors that decide the overall performance of the device. At presentthe commonly used laser shaping devices are binary optical element, a liquid crystalspatial light modulator, random phase plate, variable refractive index lens, microlensarrays and etc. In various types of laser flatting devices, microlens array has theadvantage of homogenous irradiation, easy access to material, simple manufacturingprocess and etc.At present, the fly-eye lens array is used to realize the flattened Gaussian beam.But the optical loss is rather high and the applications of fly-eye lens array aremostly limited in the field of micro projection. To simplify the structure and toimprove the energy efficiency of the microlens array laser shap ing system, asphericalmicrolens array and compact freeform microlens array are designed in this paper.Generally, the surface figure of microlens is obtained by calculating with lightfield distribution, mainly includes the physical and geometrical optics methods. Anew optimization design method based on non-imaging optics is proposed forhomogenizing the Gaussian beam. Firstly, the mathmatical expressions of light intensity distribution is established. Two dimensional coordinates of sampling rayson the incident plane and the target plane are determined. Then the optimizationfunction can be created. The surface figure of the microlens can be automaticallyoptimized in Zemax software. For the diffractive and freeform microlens array, theconvex asperical and polynomial surface figure are adopted respectively to preciselycontrol the beam’s distribution and improve the energy efficiency.In this paper, the first chapter gives an overview of the currently widespreadlaser shaping devices, the characteristics, design principles, advantages anddisadvantages as well as the field of application. Thenmainly design methods.ofmicrolens array laser shaping system are described.The second chapter introduces the basic principles of non-imaging optics,elaborate the principles of optimization design method of laser shaping system basedon the non-imaging optics.The third chapter introduces the detail Macro optimization design process fordiffractive microlens array, the model of the optimization resultis imported intoTracePro software, analyzing the spatial distribution of the light beam at a specifictarget surface..In the fifth chapter, the freeform microlens array is achieved. The optimizationresult of the freeform microlens array laser shaping system is importedinto TraceProsoftware to analyze the intensity distribution of the beam.The sixth chapter summarizes the work of master stage, making prospects forfuture work.