一种用于映射结构化偏振场的无投影方法
A projection-free approach toward mapping the structured polarization fields
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中文总结 AI 辅助
该研究提出用HOM干涉的无投影方法映射二维偏振分布，利用双光子聚束克服传统技术局限，通过特定设置实现无投影重建，展示了高保真重建及角分辨率，还介绍了可提高分辨率的估计器，为表征双折射材料偏振场提供新框架。
中文摘要 AI 辅助
我们提出一种使用Hong-Ou -Mandel（HOM）干涉来映射二维偏振分布的无投影方法。传统偏振表征技术如斯托克斯偏振imetry依赖于多个偏振投影下的顺序强度测量，其精度和灵敏度易受消光比、校准误差和偏振分析光学器件稳定性影响。我们的方法利用双光子聚束对平衡分束器处偏振不可区分性的敏感性克服这些限制。通过810nm高亮度自发参量下转换光子对源驱动HOM干涉仪，在一个干涉仪臂中引入具有空间变化偏振旋转的双折射涡旋波片，以高信噪比测量符合计数，实现对样品诱导偏振变换的无投影表征，直接将空间相关偏振变化映射到符合计数上，实现偏振分布的无投影重建。我们展示了空间偏振图案的高保真（约95%）重建，角分辨率约为0.4°。使用由费希尔信息计算得出的使克拉美-罗界饱和的估计器，可进一步提高分辨率，但采集时间会更长。所提出的量子光学技术为表征双折射材料中的结构化偏振场提供了一个简单、可扩展且高精度的框架。
英文摘要
We present a projection-free method for mapping two-dimensional polarization distributions using Hong-Ou -Mandel (HOM) interference. Conventional polarization characterization techniques, such as Stokes polarimetry, rely on sequential intensity measurements under multiple polarization projections, making their accuracy and sensitivity susceptible to the extinction ratio, calibration errors, and stability of the polarization analysis optics. Our approach overcomes these limitations by exploiting the sensitivity of two-photon bunching to polarization indistinguishability at a balanced beam splitter. Using a HOM interferometer driven by a high-brightness spontaneous parametric down-conversion photon-pair source at 810 nm, we introduced a birefringent vortex waveplate with spatially varying polarization rotations in one interferometer arm and measured the resulting coincidence counts with a high signal-to-noise ratio, enabling projection-free characterization of the sample-induced polarization transformations. This configuration maps spatially dependent polarization variations directly onto coincidence counts, providing a projection-free reconstruction of the polarization distribution. We demonstrate high-fidelity ($\sim$95$\%$) reconstruction of the spatial polarization pattern with an angular resolution of approximately $\sim0.4^\circ$. The use an estimator that saturates the Cramer-Rao bound, computed from the Fisher information, can improve resolution further at the cost of longer acquisition. The proposed quantum-optical technique offers a simple, scalable, and high-precision framework for characterizing structured polarization fields in birefringent materials.
