Coherence theory of a laser beam passing through a moving diffuser.
Coherence theory of a laser beam passing through a moving diffuser.
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DOI：
10.1364/oe.21.013032
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发表时间：
2013-06
期刊：
影响因子：
3.8
通讯作者：
Gaoming Li;Y. Qiu;Hui Li
中科院分区：
文献类型：
--
作者：
Gaoming Li;Y. Qiu;Hui Li
本文提出了激光束通过运动漫射体的一般相干理论。通过移动漫射器的激光束的时间相干性取决于两个特征时间尺度：激光相干时间和漫射器移动通过相位相关区域所花费的平均时间。在大多数应用中，前者比后者短得多。我们的理论分析表明，从一个移动的漫射器散射的光的空间相干面积减少，而相干时间保持不变。这一结论已被迈克尔逊干涉仪的实验所证实，它不符合原来的相干性理论，即光被运动漫射体散射后，其时间和空间相干性都降低了。我们还发展了一种基于特征值理论的方法来计算通过移动漫射器传输的光照射的屏幕上的散斑对比度。
We present the general coherence theory for laser beams passing through a moving diffuser. The temporal coherence of laser beams passing through a moving diffuser depends on two characteristic temporal scales: the laser coherence time and the mean time it takes the diffuser to move past a phase correlation area. In most applications, the former is much shorter than the latter. Our theoretical analysis shows the spatial coherence area of light scattered from a moving diffuser decreases while the coherence time remains unchanged. The conclusion has been confirmed by experiments using a Michelson interferometer and it is not in accordance with the original coherence theory in which both the temporal and spatial coherence of light scattered by a moving diffuser decrease. We also developed a method based on the theory of eigenvalues to calculate the speckle contrast on a screen illuminated by light transmitted through a moving diffuser.