The Study Of Beam Shaping And Phase Correction

The quality of laser beam and profile of near field intensity are the two fields which are the focus of attention for the high energy researcher. As the quality of laser beam is influenced by a lot of factors which come from the laser itself and the propagation, the adaptive optics(AO) system is the common means to control the beam. The study of theory reveals that the perfect phase conjugate is the key of system to correct aberration completely. However, the correct effect of real system is limited by a lot of reasons. Nonuniform near-field not only have a influence on laser far-field concentration ratio but also result in Nonuniform heat distortion and serious wave-front distortion. The AO system based on SPGD algorithm is a easy and effective method to accomplish this target, but the effect of beam shaping is influenced by aperture of the target beam.The dissertation's main works are listed as follows: the theoretical and experiment studies of phase correct and the improvement of the beam shaping system based on SPGD algorithm.The first part of this paper mainly analyzes the correct effect of conventional conjugate AO systems which are influenced by a lot of factors. The content mainly includes several sections as following: the derivation and analysis on aberration correction theory of conventional conjugate AO systems; we studied the correct effect of conjugate AO systems which are influenced by several factors, and offered an improved solution of correcting aberration. The two means of effect on correcting aberration were simulated. At the same time, we accomplished the light path basing on dual liquid crystal spatial lighter modulators(LC-SLM), preliminarily verifying the analysis of theory and effect of analogy.The second part of this paper mainly analyses and improves the beam shaping system based on SPGD algorithm. It includes several sections as following: improve the beam shaping system to overcome the defect of original one. The beam shaping effect of improving system and the applicability to target beam aperture were simulated and also relevant experiments were carried out. The results reveal that the improved system could have a fantasy beam shaping effect when the realistic and required target beam far away from the best target aperture, and it reaches the expected goal.