【作者】 邓亚红；

【导师】 罗斌；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2006， 硕士

【摘要】 惯性约束聚变(Inertial Confinement Fusion，ICF)是受控核聚变的常用方法之一，属于当今国际上的重大前沿基础科研领域，对国防科技和未来能源开发有着极为重要的科学意义和应用价值。新一代ICF激光驱动器的主放大器均采用多程放大结构，放大器一般由八片左右的片状放大介质级联而成。因此，理解并掌握光束在级联非线性介质中的传输特性，从而避免光束在空间传输过程中产生过强的能量甚至造成元件损伤，对于ICF驱动器的设计与建造具有非常积极的意义。 基于此，本文共分两个部分。 第一部分，首先利用菲涅耳衍射原理和傅里叶变换方法，从理论上推导了高斯光束经过级联非线性介质光传输系统后，任意位置处出射光场振幅分布的解析表达式，并在理论分析的基础上进行了数值模拟计算；分析了解析解和数值计算结果之间的误差；研究了光场强度峰值大小、峰值出现的位置以及光束的束宽和调制因子等参量在级联介质中的变化关系；分析了介质之间不同的空间配置距离对光束传输性能的影响规律。研究表明，在介质排布过程中要尽量错开光强峰值位置，为避免破坏的产生，在实际应用中要对介质排布间距进行有效的优化。 第二部分，通过数值计算的方法，对级联介质光传输系统的“热像”(hot image)效应进行了深入系统地研究，分析了“热像”的演变规律；研究了衍射物尺寸和介质排布间距对峰值光强的影响程度；得出了“热像”点的强度随介质排布间距的变化规律。研究表明，“热像”的强度与调制平面到介质入射面的距离基本上没有关系，但是与输入光束的强度和衍射物的半径有关；增大间距或者元件非周期性排列能够降低峰值光强，减轻非线性破坏的影响。更多还原

【Abstract】 Inertial Confinement Fusion (ICF) which is one of the common methods of controlling nuclear fusion plays more important role in the development of new energy resources and national defense science. ICF laser driver consists of many amplifiers. In new-model laser driver, the main amplifier which commonly has many disk amplifier mediums is multi-pass amplifier system. To avoid element damage due to super-high optical power, it is very significant to research the characteristics of optical beam passing through cascade nonlinear elements for ICF driver’s design and manufacture.The thesis consists of two parts.In the first part, the expression of Gaussian beam intensity after passing through cascade nonlinear element in arbitrary location is derived firstly by using Fresnel diffraction principle and Fourier transform method. Besides the theoretical analysis, the numerical result is introduced, and the difference between theoretical and numerical is analyzed. After this, the corresponding relations with the optical beam peak intensity, the peak power location, beam width and modulation factor in cascade elements have been studied, and then, the effect rule on the optical beam transmission characteristics induced by the space between nonlinear components has been discussed. Above studies indicate that the nonlinear element should keep away from peak intensity of optical beam by all means. It is necessary to optimize the space between nonlinear elements for avoiding element damage in practical application.In the second part, the formation of the "hot image" has been studied by numerical simulation. The variation effect of hot-image is researched. Then, by analyzing the effect of diffraction beam size and space between mediums to peak intensity, the regulation of the intensity of the "hot image" with different space between mediums has been indicated. It is shown that the intensity of the "hot image" is independent of the distance between modulate plane and input plane of更多还原