大面积拼接光栅的远场衍射分析

Far-Field Diffraction Pattern Analysis of Tiled Gratings

针对大面积光栅制作过程易出现的拼接偏差问题,基于标量衍射理论推导拼接光栅远场衍射的光强分布,计算分析几种常见拼接误差对拼接光栅性能的影响,以确定光栅拼接过程的误差容限.研究表明:拼接光栅的远场衍射光场随纵向和横向平移误差的变化呈周期性,且这两种平移误差带来的影响可相互补偿;而拼接光栅的旋转误差对远场衍射光场分布的影响较严重,当旋转误差增大到9.5875×10-5度时,衍射光场的峰值光强降为0.9,且两光栅各自峰值出现的方向成9.5875×10-5度.

Many optic engineerings such as ICF （Inertial Confinement Fusion） urgently need large-area grating.In the paper,based on the scalar diffraction theory,the intensity distribution of far-field diffraction of tiling grating is obtained and the effects of several tiling errors on grating performance are analyzed according to the possible alignment errors in the tiling progress.The calculated results indicate that the maximum intensity of far-field diffraction presents period variation with the longitudinal and transverse translation errors which can be compensated with each other,and the influence of rotating error on the diffraction filed is relatively severe.The maximum intensity will decrease to 0.9 and the separation angle between the directions of the principle maximums of two gratings is 9.587 5×10-5degree when rotating error is 9.587 5×10^-5 degree.The results will be helpful for evaluating and controlling the rotating errors.