Fourth-order moments analysis for partially coherent electromagnetic beams in random media
Fourth-order moments analysis for partially coherent electromagnetic beams in random media
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DOI：
10.1080/17455030.2022.2096272
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发表时间：
2023-11
影响因子：
--
通讯作者：
J. Garnier;K. Sølna
中科院分区：
文献类型：
--
作者：
J. Garnier;K. Sølna
本文提出了在部分相干情况下电磁波光束四阶矩特性的理论。部分相干随机源采用高斯-谢尔模型。白噪声傍轴制度被认为是，当波长远小于源的相关半径，源的光束半径，和介质的相关长度，这是远远小于传播距离。复波振幅场可以用伊藤-薛定谔方程来描述。该方程给出了各阶波场矩的闭合演化方程，这里考虑了四阶矩方程。一般的四阶矩方程显式求解的闪烁制度（当源的相关半径是相同的顺序作为介质的相关半径，但光束半径大得多），其结果给出了一个表征的强度协方差函数。强度协方差函数的形式来自与二阶波矩相关的维格纳分布的输运方程的解。极化波的四阶矩结果用于部分相干源成像的应用中。
A theory for the characterization of the fourth-order moment of electromagnetic wave beams is presented in the case when the source is partially coherent. A Gaussian–Schell model is used for the partially coherent random source. The white-noise paraxial regime is considered, which holds when the wavelength is much smaller than the correlation radius of the source, the beam radius of the source, and the correlation length of the medium, which are themselves much smaller than the propagation distance. The complex wave amplitude field can then be described by the Itô-Schrödinger equation. This equation gives closed evolution equations for the wave field moments at all orders and here the fourth-order moment equations are considered. The general fourth-order moment equations are solved explicitly in the scintillation regime (when the correlation radius of the source is of the same order as the correlation radius of the medium, but the beam radius is much larger) and the result gives a characterization of the intensity covariance function. The form of the intensity covariance function derives from the solution of the transport equation for the Wigner distribution associated with the second-order wave moment. The fourth-order moment results for polarized waves are used in an application for imaging of partially coherent sources.