光束取样光栅(BSG)是应用于惯性约束聚变(ICF)驱动器终端光学系统中的重要光学元件,它可将极小部分激光能量(约0.1％)从主光路中分离出来,为系统激光参数的精密诊断提供取样信号。然而在实际应用中,由于系统光路结构复杂,入射到BSG的光束与理想情况总存在一定的偏差,影响了BSG取样光束信号的准确性和有效性。基于菲涅耳全息记录与再现原理,建立了BSG的使用状态模型并对其光束取样过程进行了深入研究,重点分析了照明光束存在波长偏移、入射角偏差或相位畸变时,BSG取样光斑位置及其能量分布的规律。为实际工程系统中BSG的应用调整提供了参考。

Beam sampling grating (BSG) is an important optical element applied in the terminal optical system of inertial confinement fusion (ICF) drivers. It can separate a very slight part of laser energy (-0.1%) from the main beam,thus provide sampling signal for the precise diagnosis of the laser parameters. However,in application,there are always certain deviations between the incident beam lighting on the BSG′s face and the ideal one,such as the lean of incident angle,wavefront distortion,etc.. These deviations affect the accuracy and validity of BSG′s sampling signal. In this paper,a model of BSG′s using state is established based on the theory of Fresnel holographic recording and representation,and the process of beam sampling is further studied. This paper emphatically analyzes the location and energy distribution of sampling spot when light wavelengths have wavelength shift,incident angle deviation or wavefront distortion. The analysis results of this paper provide theoretical reference for practical engineering of BSG in application system.