A model to calculate the optical field distribution of quadruplet beams on a hohlraum target wall is pre-sented. This model combines geometrical ray tracing, coordinate transformation, and Fresnel diffractionintegral to capture the quadruplet beams propagating in four different directions and the typically non-planar geometry of the hohlraum wall. The results demonstrate that the optical field distribution arisesmainly from individual beam diffraction, and the interference with other beams in the quadruplet hardlydevotes to the distribution. A movie is also produced to interpret the spatio and temporal evolution ofthe optical field on a cylindrical hohlraum wall.

Three-dimensional spatio-temporal variation characteristics of pulse intensity is numerically simulated in detail in multi-pass amplifier of high power laser system. Theoretical calculation indicates that the complicated spatio-temporal distortion occurs as the pulse with specific spatio-temporal distribution passes the amplifier. This change imposes some difficulties on shaping prediction of the pulse power. The curve fitting method of input-output integral energy is proposed to achieve the inverse prediction of inject pulse shape formulti-pass amplifier system with high precision. The better prediction result is achieved not only for square pulse shape but also for multiple-steps complex pulse output, the relative power deviation reaches up to 0.032% for the square pulse output, and 0.78% for multiple-steps complex pulse output. In addition, the inverse prediction of more complicated Haan pulse is achieved. The relative power deviation is 0.13%. This method has not only high precision but also rapid computation and strong applicability.

对高功率激光多程放大系统中脉冲强度的三维时空变化特性进行了详细的数值分析，理论计算表明具有一定时空分布的光束在放大过程中会产生复杂的时空演化畸变，给脉冲功率的整形预测带来了一定的难度。提出了输入输出积分能量曲线拟合的方法，实现对多程放大系统输入脉冲波形的高精度反演预测，对于方波和复杂多台阶波形输出都能得到很好的预测结果，方波预测相对功率偏差低于0.032%，三台阶脉冲相对功率偏差为0.78%，另外还实现了更为复杂Haan脉冲的反演预测，相对功率偏差为0.13%。该方法不仅精度高，而且计算快速、适用性很强。

高功率激光装置中通过测量光束强度分布来评价近场光束质量。然而测量结果为一稳态分布，并不能真实反映经噪声扰动后光束的强弱调制演变特性，可能会忽略传输过程中存在的调制较为严重的区域。针对此问题着重研究了光束经噪声扰动后的近场传输演化特性，进而对近场分布测量的局限性进行深化理解和补充。同时，为简化分析单因素局部缺陷影响下不同传播距离处的近场分布变化规律，引入等效菲涅耳数来表征近场强度调制特性。结果表明，当实测近场分布中存在较弱调制信息时，测量位置之前可能存在更为严重的调制区域。以调制为π的位相型缺陷为例，其最大调制相对于入射光强度可增大9倍。

For high-power laser facility, sub-beams caused by multiple defects of opitcal component surface with different distributions interfere with each other in the transmission process, bringing about complex changes in beam quality. So it is necessary to make a clear limitation on relative position of defects. On the basis of the diffraction transmission theory, when there are scratches with different spatial distributions on the optical element surfaces, the changes of beam modulation are studied. The influence of scratch depths on the distribution of near field beam modulation is also taken into account. Results show that when two parallel or vertical scratches are on the same or different surfaces of an element. Both of them produce more serious modulation than single scratch, and the maximum modulation degree can be increased to 1.5 times. Meanwhile more strict requirements for scratch depth are put forward. The results can provide reference for the revision of optical element standard and the determination of defects specifications for large- diameter elements in high-power laser systems.

针对高功率激光装置，光学元件表面不同分布形态的多个缺陷引起的子光束，在传输过程中会相互干涉叠加，引起光束质量发生复杂变化，因此有必要对缺陷的相对位置关系加以规范。基于光的衍射传输理论，研究了光学元件表面存在不同空间分布的划痕时光场调制的变化，以及划痕深度对调制光束近场分布的影响。结果表明，元件前后表面存在平行或垂直划痕时均会比单一划痕产生更加严重的光束调制，最大调制度可增至1.5倍，且划痕具有更严格的深度要求。研究结果为光学元件图形制备标准的补充及高功率激光装置大口径光学元件表面缺陷指标的确定提供了重要参考。