Joshi Rajneesh, Kanseri Bhaskar
J Opt Soc Am A Opt Image Sci Vis. 2021 Feb 1;38(2):271-276. doi: 10.1364/JOSAA.408804.
We establish the concept of cross-spectral purity for nonstationary electromagnetic fields having any degree of coherence or polarization. The conditions of cross-spectral purity in all Stokes parameters are derived for both space-time and space-frequency domains, which demonstrate that the normalized two-point coherence properties of such fields can be expressed as products of a spatial and a time (or frequency) dependent function. We further determine the condition of strict cross-spectral purity for nonstationary fields, which establishes the equivalence of normalized two-point Stokes parameters governing the spatial factors of the space-frequency and space-time domains. This study may provide interesting aspects of statistical properties of beams obtained from practically available sources such as pulsed lasers, modulated and fluctuating light sources, etc.
我们建立了具有任意相干度或极化程度的非平稳电磁场的交叉谱纯度概念。推导了时空域和空间频率域中所有斯托克斯参数的交叉谱纯度条件，这表明此类场的归一化两点相干特性可表示为空间函数与时间（或频率）相关函数的乘积。我们进一步确定了非平稳场的严格交叉谱纯度条件，该条件确立了控制空间频率域和时空域空间因子的归一化两点斯托克斯参数的等效性。本研究可能为从实际可用光源（如脉冲激光器、调制和波动光源等）获得的光束的统计特性提供有趣的方面。
