关联交换：用于独立热光源的关联器
Correlation Swapping: a correlator for independent thermal light sources
AI总结：
该研究提出经典关联交换概念，构建关联器实现独立热光源的空间关联，完成首个经典鬼成像实验，为无关联经典光的光学应用开辟新方向。
AI中文摘要：
光强关联是光的基本属性，也是众多光学应用的核心资源。本研究引入经典关联交换的概念，它是量子纠缠交换的经典类比，用于在两个独立热光源之间生成通用空间关联。利用空间未分辨的马赫-曾德尔干涉仪和一个介质变量，我们从理论和实验上验证了该关联器的可行性，针对独立伪热光束提出了两种不同方案。值得注意的是，所得光子关联可被轻易调整以呈现聚束（峰值）或反关联（谷值）特性，且后选择测量的数量显著减少。借助该经典关联器，我们进一步完成了首个使用无关联或未知光的经典鬼成像实验。数值模拟还证实，该关联器不仅能在其他空间自由度（如轨道角动量）中良好运行，还可用于在具有不同关联特性的伪热光源之间建立特定空间关联。本研究为在基于关联的光学应用中利用无关联经典光开辟了新途径。
英文摘要：
Optical intensity correlation is a fundamental property of light and an essential resource for numerous optical applications. In this work, we introduce the concept of classical correlation swapping, a classical analogue of quantum entanglement swapping, to generate all-purpose spatial correlations between two independent thermal light sources. Using a spatially unresolved Mach-Zehnder interferometer and a medium variable, we theoretically and experimentally demonstrate the feasibility of the correlator with two distinct schemes for independent pseudo-thermal light beams. Notably, the resulting photon correlations can be readily tailored to exhibit either bunching (peak) or anti-correlated (dip) characteristics, with a significantly reduced number of post-selection measurements. Leveraging this classical correlator, we further demonstrate the first classical ghost imaging experiment using uncorrelated or unknown light. Numerical simulations also confirm that the correlator can not only operate well in other spatial degrees of freedom (e.g., orbital angular momentum) but also be used to establish specific spatial correlations between pseudo-thermal light sources possessing distinct correlation properties. This work opens a new avenue for harnessing uncorrelated classical light in correlation-based optical applications.
