【作者】 张永生；

【导师】 王洪祥；

【作者基本信息】 哈尔滨工业大学 ， 机械（专业学位）， 2022， 硕士

【摘要】 连续相位板(Continuous Phase Plate,CPP)和聚焦非球面透镜是激光惯性约束聚变系统中两个独立的组成元件,如果能够实现聚焦非球面透镜和连续相位板的功能融合,不仅可以降低激光系统的维护难度,还能简化光学元件的加工工艺流程。为此开展了强激光聚焦与焦斑束匀滑自由曲面结构设计、复杂曲面磁流变加工去除函数建模及采斑实验、复杂曲面光学元件磁流变加工实验以及复杂曲面磁流变加工轨迹规划及实验等研究工作,取得了如下成果:基于改进的G-S算法,利用CPP自开发软件设计出九种不同相位结构的CPP,并以最大梯度和PV最小、焦斑能量利用率最大为目标,对CPP相位结构进行了优选。分析了非球面透镜性能参数对焦距的影响规律,并通过波长λ和楔角θ的大小计算出非球面楔形透镜的偏转角δ,进而确定出透镜焦点位置。对比分析了连续相位板和非球面透镜融合前后光路的差异,得到了融合元件的相位分布,根据标量衍射模拟方法,计算出融合元件的远场焦斑能够满足系统使用要求。基于Preston方程,通过实验确定了与元件材料特性、磁流变液成分以及机床性能相关的Preston系数K,在平面、球面元件磁流变抛光去除函数模型的基础上,对非球面的进行了局部分区处理,将局部非球面拟合为球面,建立了非球面元件磁流变抛光去除函数模型,并编写了抛光斑模拟采斑软件、非球面动态抛光斑阵列软件。研究了不同工艺参数对去除函数体积去除率和峰值去除率的影响规律,实验结果表明:浸入深度对去除函数体积去除率的影响程度最大,转速对峰值去除率的影响程度最大。通过磁流变加工过程中切削力的变化判断去除函数和去除过程的稳定性和均匀性,最后根据切削力数学模型实现了磁流变抛光工艺参数优选。分析了轨迹波纹误差产生原因,通过仿真分析了变间距光栅加工、摆线加工对波纹误差的抑制效果,结果表明:两种加工方式均能实现对轨迹波纹误差的有效抑制,且摆线加工轨迹对波纹误差抑制效果更明显。最后开展了复杂曲面连续位相板磁流变加工实验,得到了高质量的功能融合光学元件,其面形残差仅为13.367nm,标量衍射模拟计算结果表明功能融合元件的远场焦斑质量能够满足系统使用要求。更多还原

【Abstract】 Continuous Phase Plate(CPP)and the focusing aspheric lens are two independent components of the laser inertial confinement fusion system.The functional integration of focused aspheric lenses and continuous phase plates not only reduces the maintenance of the laser system,but also simplifies the processing process of optical components.To this end,the research work of strong laser focusing and focal spot beam uniform-slip freeform structure design,complex surface magnetorheological processing removal function modeling and spot collection experiment,complex surface optical component magnetorheological processing experiment and composite freeform magnetorological processing trajectory planning and experiment has been carried out,and the following results have been achieved:Based on the improved G-S algorithm,the CPP phase structure of nine different phase structures is designed by using CPP design software,and the CPP phase structure is optimized with the goal of maximum gradient and PV minimum and focal spot energy utilization maximization.The influence of aspheric lens performance parameters on focal length is analyzed,and the deflection angle δ of aspheric wedge lens is calculated by the size of wavelength λ and wedge angle θ,and then the focal point position of the lens is determined.The difference between the optical path before and after the fusion of continuous phase plates and aspheric lenses is compared and analyzed,the phase distribution of the fusion elements is obtained,and the far-field focal spot of the fusion components is calculated according to the scalar diffraction simulation method to meet the requirements of the system.Based on the Preston equation,the Preston coefficient K related to the material characteristics of the component,the composition of the magnetorheological fluid and the performance of the machine tool was determined through experiments,and on the basis of the model of the magnetorological polishing removal function of the planar and spherical components,the local aspheric surface was partially partitioned,the local aspheric surface was fitted to the spherical surface,the magnetorheological polishing function model of the aspheric component was established,and the polishing spot simulation spotting software and the aspheric dynamic polishing spot array software were written.The influence of different process parameters on the volume removal rate and peak removal rate of the removal function is studied,and the experimental results show that the immersion depth has the greatest influence on the removal rate of the removal function volume,and the speed has the greatest influence on the peak removal rate.The stability and uniformity of the removal function and the removal process are judged by the change of the cutting force in the magnetorheological machining process,and finally the magnetorheological polishing process parameters are optimized according to the mathematical model of the cutting force.The causes of trajectory ripple error are analyzed,and the inhibition effect of variable pitch grating processing and cycloidal processing on ripple error is analyzed by simulation,and the results show that the effective suppression of trajectory ripple error can be achieved by both processing methods,and the effect of cycloid processing trajectory on ripple error is more obvious.Finally,the magnetic rheological processing experiment of the composite surface continuous phase plate was carried out,and the high-quality functional fusion optical component was obtained,and the surface residual was only 13.367 nm,and the scalar diffraction simulation results showed that the far-field focal spot quality of the functional fusion component could meet the system requirements.更多还原