云纹法检测变线距光栅的线密度

Measurement of the line-density of a varied-line-space grating by Moiré fringe

变线距光栅在同步辐射装置、激光核聚变装置上有着广阔的应用前景 ,它的制作和检测方法尚未成熟 ,本文在介绍变线距光栅线密度变化规律的基础上 ,采用级数形式表达变线距光栅线密度 ,比较了几种测量方法后 ,将云纹法引入变线距光栅的检测中 ,从理论上介绍了几何云纹法和云纹干涉法 ,几何云纹法适合于线密度很低的光栅 ,云纹干涉法适合于线密度较高的光栅 ,云纹的密度反映了光栅的线密度 ,如果云纹非常密 ,精确地测量所有云纹的坐标比较难 ,可以用数云纹数目的方法测出光栅的密度变化 ,就变线距光栅的检测分别给出了有关理论公式 ,并给出实际测量中的光路和初步的结果 。

Varied_line_space gratings are very useful in synchrotron radiation devices and laser inertial confinement fusion devices, but there are no good ways to measure and manufacture them.In this paper the line_density of a varied_line_space grating is outlined, which is expressed by power series. In comparison with other methods, the Moiré fringe method is introduced, Moiré and Moiré interferometry discussed. The Moiré is used to check the gratings with very low density; while the Moiré interferometry is used in the gratings with high density. The density of Moiré fringes shows the line density of a grating. If it is very high, the coordinates can not be surveyed exactly, the line_density of a grating can be achieved by counting the number of Moiré fringes. Some formulae are deduced, and the data processing method is given. Finally, the author explains the optical alignment of Moiré interferometry.