Cheng Y S
Appl Opt. 1989 Feb 1;28(3):556-64. doi: 10.1364/AO.28.000556.
The fringe characteristics in four-beam cross-grating interferometers, illuminated by a source at finite distance, are analyzed. From the measurements of the fringe visibilities and the fringe shifts on discrete planes, the spatial irradiance distribution of the illuminating source which is separable in two orthogonal directions can be synthesized. When the line structures of the two cross gratings are not parallel, the fringe pattern has lower contrast which suggests that four line gratings should be used to replace the second cross grating in order to have high contrast fringes. The possibility of forming cross-gratinglike patterns using either a combination of one cross grating and two line gratings or a combination of two line-grating interferometers is discussed. Finally, moire interferometry using a cross-grating interferometer is suggested.
分析了由有限距离光源照明的四光束交叉光栅干涉仪中的条纹特性。通过在离散平面上测量条纹可见度和条纹位移，可以合成在两个正交方向上可分离的照明光源的空间辐照度分布。当两个交叉光栅的线结构不平行时，条纹图案的对比度较低，这表明应使用四个线光栅来代替第二个交叉光栅，以获得高对比度条纹。讨论了使用一个交叉光栅和两个线光栅的组合或两个线光栅干涉仪的组合形成类似交叉光栅图案的可能性。最后，提出了使用交叉光栅干涉仪的莫尔干涉测量法。
