Research On Gaussian Beam Spatial Domain Homogenization Technology Based On Phase Modulation

In recent years,lasers have become more and more widely used in information technology,electronic circuits,medical devices,and welding processing.In practice,the lateral distribution of the beam emitted by the laser is Gaussian,which limits its application range.Therefore,for a specific use scenario,the laser beam needs to be shaped to obtain a specific energy distribution.In this paper,the single-mode Gaussian beam is shaped as the flat-top beam as an example.The spatial beam shaping homogenization technology based on phase modulation is studied and analyzed.The microlens array homogenization system and the liquid crystal spatial light modulator homogenization system are respectively carried out.An experiment was designed to verify the simulation results.In this paper,the transmission process of Gaussian beam and super Gaussian beam is theoretically analyzed,and the light intensity distribution under normal conditions is obtained.The simulation model of Gaussian beam is established in MATLAB,and the 40-order super Gaussian beam is selected as the target flat-top beam.The phase modulation effect of Liquid Crystal Spatial Light Moudulator(LCSLM)is analyzed,and the energy uniformity and energy utilization comprehensive evaluation model is introduced as the evaluation index of simulation and experimental results.The computational model of the microlens array homogenization system is studied from the perspectives of geometric optics and physical optics,and the phase modulation of the lens elements is analyzed.The parameter design and simulation experiments of non-imaging and imaging microlens array homogenization systems were carried out by using TracepPro software.The key parameters affecting the homogenization effect were studied,and an error analysis model was established for the imaging homogenization system.The beam homogenization physical model of LCSLM is established,and the design idea of phase recovery algorithm combined with LCSLM is proposed.The simulation design and experiment of pure phase liquid crystal spatial light modulator are carried out.The common phase recovery algorithm is introduced,and the initial phase is generated by the two schemes and the experiment is repeated 30 times by G-S algorithm.Finally,the Gaussian initial phase with better homogenization effect is selected.The Gaussian type is selected for the initial phase,and the simulation analysis is carried out by GAA algorithm.The conclusion that the homogenization effect of GAA algorithm is better than G-S algorithm is obtained.The GAA algorithm is used to design the phase distribution and convert it into a 256-order phase grayscale image.Therefore,the phase distribution obtained by the GAA design is converted into a 256-order phase grayscale image,and the error generated when the phase modulation depth in the range of 0-2? is quantized by 256 th order is quantitatively analyzed.The phase gray scale image is loaded on the LCSLM under laboratory conditions,and the outgoing beam is measured and evaluated.The homogenization result is basically consistent with the simulation experiment,and the purpose of shaping the Gaussian beam into a parallel flat-top beam is realized.