And the techniques of double-slitfilter and "cross-filter" can be used to extract the near field wavefront of the laser beam with phase modulation and amplitude fluctuation.
而且，利用双狭缝滤波和“交叉滤波”技术能够提取出具有位相调制或者是具有振幅起伏的近场波面。
2
According to spatial filter character, a common slit can become a practical optical filter by adding two couples of shades.