【作者】 董卫斌；

【导师】 陈良益；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 光学工程， 2008， 博士

【摘要】 驱动器是实现可控惯性约束核聚变的关键环节。由于激光脉冲能够产生高能量密度的束流,并具有强相干性,能够在时间、空间上聚焦到ICF所要求的强度,可以成为ICF的理想驱动器。本文针对激光光束控制与参数测量工程中的几个相关问题和关键技术进行了探讨。1.用干涉测量技术来评估激光波前测量系统的装调在强激光波前测量像传递系统中,4-f光传输系统透镜之间装调过程产生的离焦量引入了一个相位调制。首先从实验上测量了像平面处波面横向剪切干涉图样,利用矩阵光学和Collins衍射公式推导出了离焦量和激光波面横向剪切干涉条纹之间的理论关系,并得到了在无离焦情况下激光传输的空域和频域方程。对实验测量得到的干涉条纹空间灰度曲线利用最小二乘法进行了余弦曲线拟合,得到干涉条纹空间尺度,利用理论关系计算得到了离焦量的数值,实现了对像传递系统装调过程的定量描述。本实验方法和结果为激光参数测量系统在线使用状态调节提供了依据和参考。2.分析了离轴四程放大系统前端腔镜准直采用的小孔像传递工作原理激光束的精密准直系统是目前大型激光装置的一项关键技术,针对离轴四程放大系统前端腔镜准直采用的小孔像传递工作原理进行分析,由Collins衍射公式出发,利用矩阵光学理论推导了监视小孔出射光场复振幅分布的描述方程,并设计了腔镜调整的监视光学系统。论文完整地提出了准直流程中的难点—腔镜准直光学监测镜头设计的物理特征描述,并利用图像边缘特征进行腔镜调节的图像处理仿真研究。基于国内惯性约束装置总体对腔镜准直调整流程,针对高功率激光系统腔镜准直过程光斑图像,利用仿真方法定量分析了光斑边缘特征,结合腔镜准直监测单元光传输的特性,使用激光光斑边缘不同部分曲率的相似性和光斑圆形度,实现对腔镜调节的量化评估。3.研究了近远场光斑测量光学系统中的光学瑕疵对图像调制的影响光斑的近场分布是描述大型激光系统光束质量的重要内容。本文从物理光学角度定性的分析了激光近场调制的因素,即入射光束自身的特征分布、光阑效应以及由于衍射效应形成的调制,并进行了一系列模拟计算。在激光光束传输过程中,由于测量系统的瑕疵,会在这个地方产生激光能量密度集中,光学元件易损。针对工程需要,本文设计了一种强激光参数测量系统光学元件瑕疵在线检测的辅助光学系统。在设计中充分考虑了测试系统的使用空间,采用了光阑后置的准远心光路,并用CCD器件来检测。论文对上述研究内容的创新点进行了总结,并对今后的一些研究工作提出了建议。更多还原

【Abstract】 The drive facility is the key technical step for controlling the inertial confinement fusion(ICF).The high power laser facility is selected as the ideal ICF drive device for the reason that the laser can produce the high power intensity and spatial interference which meet the temporal pulse length and shape requirements for physical experiments.The assistant optical issue and key technique of beam control and parameter diagnostic in high power laser system are discussed in this paper.1.The shear interferometer method is used in evaluating installing status of the beam image-relaying test system.In the distribution measurement image-relaying system of high power laser,the phase modulate is produced by the laser converge point diverged from the lens focus in axis between two lens in 4-f system as the test system installed.First the interference pattern in the image plane of the 4-fsystem was measured using sheared interference laterally experiment.And the academic relationship between the off-focus values and interferential fringe interval using lateral sheared interference test method was deduced by the matrix optic theory and Collins diffraction equation. The laser transmission relationship in space and frequency are also derived in the condition of where having no off-focus values.The interference pattern gray-level curve was fitted using minimum mean-square error method,and the off-focus values was calculated by the interferential fringe interval which is received using curve fitting.The installing states of the test system are quantity expressed using the off-focus values.This interference algorithm can be used for quantitative describing the in-line working status of beam near-field measurement image-relaying system.2.The algorithm for aligning cavity mirror which applied in off-axis four-pass amplifier high power laser facility is detailed analyzed in this paper.The beam automatic alignment is the key technique of high power laser system. Aiming at the scheme of using image-relaying of pinholes in multi-pass amplifier, the laser field distribution was deduced using Collins diffraction theory based on matrix optic method.The measurement optical system was designed for test the alignment of the cavity mirror,and this test system is also applied in the simulation physical experiment.The physical character describing of measurement optical system designing for aligning cavity mirror and algorithm study of far-field image processing in aligning cavity mirror based on edge curve characters are developed in this paper.Based on the ICF prototype facility requirement for aligning the cavity mirror,aiming at the laser image in aligning cavity mirror of high power laser system,the edge characters of light are quantitative analyzed by image processing. Combining the light transfer qualitatively analysis of measurement optical system for aligning cavity mirror,the consistency of different curve edge and the circular degree of the laser image are used for quantitative estimated the azimuth of cavity mirror.3.The light modulating in laser near-field beam imagery was studied in this paper,which is caused by the optical component flaw mainly in the near/far laser field distribution measurement system.Near field diagnostic is an important parameter for ICF laser performance.The reason which causes dark spots fringes in laser near field distribution are qualitative analyzed from physical optics viewpoint.The light modulation is the associated effect between laser distribution,optical aperture and laser diffractive phenomenon. A series academic calculation was done in this paper to simulate this physical phenomenon.As the influence of the flaw in optical component,the laser induced damage is potential exist the place where the laser energy density is very high. Aiming at the engineering requirements,an assistant measurement optical lens was designed for online inspecting optical flaw using in laser parameter sensor packages in this paper.According to the requirement of limited working space,the structure of lenses is a stop iris postposition which field nearly views telecentric,and optical image is obtained directly with CCD cameras.Finally,the working emphasis in this paper is summarized,and some advice is also put forward to the potential assistant technical research areas in the beam control and parameter measurement system.更多还原