对变线距光栅干涉测量中的环形条纹的分析

变线距光栅能够自动聚焦和消像差,在同步辐射装置、激光核聚变装置上有着广阔的应用前景,本文用干涉法测量变线距光栅的密度,设计并给出了实验中的光路,发现了环形的干涉条纹和变化规律,分析了这些现象产生的原因,产生明显的环形条纹的必要条件首先是变线距光栅的线密度单调变化的,连续增加或连续减小,其次要光栅的刻线是弯的,第三虚栅的密度接近待测光栅的整数倍,由于元件位置偏差,检测用的平面波会变成球面波,也会产生环形的干涉条纹,但是这种效应可以忽略.预言了类似双曲线的干涉条纹.通过对条纹运动规律的分析,可以在初步测量中定性分析光栅密度的变化趋势,从而为进一步测量做准备.

Explanation of the round interference fringes in the measurement of varied-line-space gratings

Varied-line-space gratings can correct aberrations,and they are useful in synchrotron radiation devices and laser inertial confinement fusion devices. In this paper, the line-density of varied-line-space gratings is measured with interferometry. The design of optical alignment is given, and the round interference fringes and their changes are observed in experiments. The prerequisite of round interference fringes is that the density of gratings is monotone, and the density of virtual grating divided by a integer is close to it, but the grooves are curved. The fringes that hyperbolas are predicted.