基于多块光栅拼接理论,建立了光栅旋转角与衍射光束偏角关系的数学模型,设计了一种基于干涉法的光栅旋转角度检测光路,用Zygo干涉仪实现了光栅0级与1级衍射波前检测,并研究了反射镜安装误差引起的模型误差。实验结果表明,利用理论模型对光栅姿态在0~500 μrad内调整时,光栅间栅线平行度的最大相对测量误差为3.85%。而反射镜俯仰角和偏摆角在0″~20″变化时,所引起的光栅间栅线平行度的最大相对测量误差分别为4.99%和3.77%。

Herein, a mathematical model of the relationship between grating rotation angle and diffraction beam deflection angle was established based on the theory of mosaic gratings. An optical path was designed to detect the grating rotation angle using interferometry. A Zygo interferometer was used to detect the zero- and first-order diffraction wavefronts of a grating. In addition, the model error caused by the reflector installation error was studied. The experimental results show that in the range of 0-500 μrad, the maximum relative measurement error of grid line parallelism between gratings is 3.85% when the theoretical model is used to adjust the grating attitude. When pitch and yaw angles of the reflector vary in the range of 0″-20″, the maximum relative measurement errors of grid line parallelism between gratings are 4.99% and 3.77%, respectively.