中文摘要：

在用双光栅法测微小位移的实验中,光拍信号出现与理论不符的包络。经过实验分析,发现形成包络的原因是单振动光栅的衍射光边缘的强度变化。进一步分析表明,这是由于光栅振动的同时伴随有转动造成的。在振动光栅后加狭缝抑制衍射光的边缘部分,可以很好地消除光拍信号中的包络。

英文摘要：

In the experiment of measuring of tiny displacement with double gratings,the amplitude of the resultant light signal changes,forming a sine envelope,which is inconsistent with the theory.The experimental analysis found that the intensity in the edge of diffraction light of one vibration grating changes.Further analysis shows that the associated rotation in the librations of the tuning fork arm causes the change of the diffraction light intensity,and more,the envelope of the resultant light signal.If a narro...