用稳相积分法分析了点光源经过2个平行放置的有限宽平面透射光栅组成的系统衍射后的复振幅分布。当两光栅满足双光栅成像条件时, 将其衍射成像与无限宽双光栅衍射成像进行对比, 得到有限宽光栅对双光栅衍射像的位置没有影响, 而衍射像随两光栅之间的相对距离及衍射级数而变化。文中计算了满足双光栅成像条件时, 某实验参数下衍射像的大小的情形, 结果有限宽双光栅成像被放大了1.22倍。并根据其原理进行白光再现普通透射全息图色彩研究。

The complex amplitude distribution of diffraction light was analyzed by stationary phase integral method, when the point light source was passing through the system composed of two parallel placed transmission gratings with finite width. When the bi-grating imaging condition was satisfied, the comparison between the diffraction image of finite-width bi-grating and that of infinitely wide bi-grating was conducted. It is concluded that the position of bi-grating diffraction image has no effects from the finite-width grating; however,the size of diffraction image is affected by the relative distance and diffraction orders between two gratings. The size of diffraction image was calculated, which was enlarged by 1.22 times, when the condition of bi-grating imaging and some experimental parameters were satisfied. Furthermore,the study on the color of white light ordinary transmission hologram was done based on its principles.