Ding Yi, Zhao Daomu
Opt Express. 2019 Oct 28;27(22):32789-32800. doi: 10.1364/OE.27.032789.
In the light of the perspective of statistical similarity, we examine the maintenance of the second-order coherence of a light wave on weak scattering from a random medium. Some new and nontrivial results relating to properties of the scattered field which remains the second-order coherence of the incident field are presented. By assuming that the scattered field remains the second-order coherence, we can show that all of higher order correlation functions of Fourier component of the scattering potential can reduce to the like-factorization forms with a series of constant coefficients. These coefficients furnish an efficient and direct way to describe the higher order coherence property of the scattered field. We also show that the combination of the maintenance of second- and fourth-order coherence implies the scattered field coherence to all orders. Finally, the structure feature of the random medium is also discussed when the coherence of the incident field is retained up to 2nth order, in particular, in the case of the second-order coherence. Our theory is an important contribution for understanding of spatially fully coherent scattered fields, and also gives a general and new method to discuss the variation of the coherence of the scattered field.
从统计相似性的角度出发，我们研究了光波在随机介质中的弱散射情况下二阶相干性的维持情况。给出了一些与散射场性质相关的新的重要结果，该散射场保持了入射场的二阶相干性。通过假设散射场保持二阶相干性，我们可以证明散射势的傅里叶分量的所有高阶相关函数都可以简化为具有一系列常数系数的类因式分解形式。这些系数提供了一种有效且直接的方式来描述散射场的高阶相干特性。我们还表明，二阶和四阶相干性的维持相结合意味着散射场在所有阶次上的相干性。最后，当入射场的相干性保持到第2n阶时，特别是在二阶相干的情况下，我们也讨论了随机介质的结构特征。我们的理论对于理解空间完全相干的散射场具有重要贡献，并且还给出了一种通用的新方法来讨论散射场相干性的变化。
