Chang Nien-An, George Nicholas, Chi Wanli
The Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
J Opt Soc Am A Opt Image Sci Vis. 2011 Feb 1;28(2):245-54. doi: 10.1364/JOSAA.28.000245.
We present a careful theoretical analysis for the wavelength decorrelation of speckle intensity that occurs when plane-polarized laser illumination is propagated through an optical system consisting of a thick diffuser in cascade with the space-invariant 4F imaging system and a CCD monitoring configuration. Based on Maxwell's equations for propagation into the right half-space, our formulation for a scalar component of the electric field is accurate well inside of the Fresnel zone and in the nonparaxial regime as well. The diffuser is described as an artificial dielectric consisting of tiny dielectric spheres embedded in a host medium and randomly spaced. We model the thick diffusers using a thin multilayer decomposition, and we write computer software describing the output speckle pattern amplitude which results from the propagation of an input plane wave. This model provides a good description for opal milk glass (OMG), and we illustrate the usefulness of this software by two applications. First, for a series of OMG diffusers of varying thickness, we present curves for the wavelength decorrelation of speckle that are found to be in good agreement with earlier experiments by George et al.[Appl. Phys. 7, 157 (1975)]. Also, these results are used to compute internal parameters of these diffusers. Second, using these values, we present some first-order statistics of the intensity for this diffuser series and show that they are in accord with the published literature.
我们对散斑强度的波长去相关进行了细致的理论分析，这种现象发生在平面偏振激光照明通过一个由厚扩散器与空间不变4F成像系统级联组成的光学系统以及一个电荷耦合器件（CCD）监测配置时。基于麦克斯韦方程组在右半空间的传播，我们对电场标量分量的公式在菲涅耳区内以及非傍轴区域内都具有良好的准确性。扩散器被描述为一种人工电介质，由嵌入主体介质中且随机分布的微小电介质球体组成。我们使用薄层多层分解对厚扩散器进行建模，并编写了计算机软件来描述输入平面波传播所产生的输出散斑图案振幅。该模型对乳白玻璃（OMG）有很好的描述，我们通过两个应用实例来说明该软件的实用性。首先，对于一系列不同厚度的OMG扩散器，我们给出了散斑波长去相关的曲线，发现其与George等人早期的实验结果[《应用物理》7, 157 (1975)]吻合良好。此外，这些结果还用于计算这些扩散器的内部参数。其次，利用这些值，我们给出了该扩散器系列强度的一些一阶统计量，并表明它们与已发表的文献一致。
