中文摘要：

针对惯性约束聚变（ICF）终端光学系统对元件数量及厚度的限制,利用衍射光学元件（DOE）易于集成的优点,可将终端光学系统中实现不同功能的DOE元件集成于一体,以优化系统的结构和性能.为了对ICF终端光学系统集成光学元件在强激光条件下的正常运行提供分析的依据,采用傅里叶模式理论分别对色分离光栅（CSG）和色分离光栅-光束取样光栅（CSG-BSG）集成光学元件内部的近场调制特性进行了模拟计算.计算发现,将CSG与BSG集成以后其每一层的最大调制度比集成以前小10%—47%,但其激光诱导损伤风险和单个CSG一样仍然较多地存在于光学元件分界面附近.另外,通过对CSG和CSG-BSG集成光学元件出射面后1μm近场区域的光场分布和出射后0.001和0.8μm横截面光场分布情况进行的比较分析得出,集成光学元件在实现谐波分离和光束取样功能的同时,几乎没有改变出射光场分布的情况,能较好满足ICF驱动器的要求.

英文摘要：

Aiming at restricting the number and the thickness of elements used in the inertial confinement fusion （ICF） system and utilize the characteristic of easy integration of diffractive optical element （ DOE）, we can integrate different DOEs in one optical element for the system optimization in the final optics assembly. In order to lay a theoretical foundation for normal running of combined elements used in the ICF system under strong laser irradiation, this paper uses Fourier modal method to simulate the modulation characteristics of single color separation gratings （CSG） and the color separation gratings-beam sampling gratings （CSG-BSG） combined optical elements in the near field, respectively. We found that the maximal modulation of every layer of CSG-BSG combined optical element was 10 % to 47 % smaller than that of single CSG. However, the probability of laser induced risk for CSG-BSG combined optical element is also in the interface of every layer as in single CSG. In addition, through comparison of the simulated distribution of optical amplitude in the area from exit surface to 1 μm for CSG and CSG-BSG elements with the cross section distribution of optical amplitude after transmitting 0.001 and 0. 800 μm for the two optical elements, it was shown that CSG-BSG combined optical element can realize both harmonic separation and beam sampling, but hardly change the exit optical field distribution. So CSG-BSG combined optical element can meet the requirement for the ICF driver.