We revisit the concept of optical spatial coherence by considering the case of the complex degree of spatial coherence induced over a plane by a quasi-monochromatic irradiating source. We apply the Van Cittert–Zernike theorem and exploit a Lloyd’s two-beam interferometer setup with its two small coherent light sources, as a way to illustrate the calculation of such complex spatial coherence, and because such setup offers a simple way to vary the separation d between its two irradiating sources, which then allows one to analytically obtain the functional dependence of the complex spatial coherence upon that separation d . We then consider the more general case in which the two small light sources of the experimental setup are spatially incoherent and again obtain the complex degree of coherence over a plane. This provides a simple, yet rigorous way, to present the subject of spatial coherences and field correlations to undergraduate physics students. An interesting l...

中文翻译：

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准单色光源在平面上的复杂空间相干度

通过考虑准单色辐射源在平面上引起的复杂空间相干度的情况，我们重新讨论了光学空间相干的概念。我们应用Van Cittert–Zernike定理，并利用带有两个小相干光源的劳埃德（Lloyd）双光束干涉仪设置，来说明计算这种复杂空间相干的方法，并且因为这种设置提供了一种简单的方法来改变分离度d在其两个辐射源之间，然后允许一个人解析地获得复杂空间相干对分离d的函数依赖性。然后，我们考虑更一般的情况，其中实验装置的两个小光源在空间上不相干，并且再次获得平面上相干的复杂程度。这提供了一种简单但严谨的方法，向大学物理专业的学生介绍空间相干性和场相关性的主题。一个有趣的...