正交堆叠范德华NbOCl₂晶体实现的偏振纠缠
Polarization entanglement enabled by orthogonally stacked van der Waals NbOCl2 crystals
AI总结：
针对范德华NbOCl₂晶体因非线性极化率张量无法产生偏振纠缠的问题，研究利用其扭转堆叠自由度实现了可调谐偏振纠缠与量子Bell态制备，提供了新型纠缠光子源与纳米级纠缠调控新手段。
摘要：
偏振纠缠对光子量子技术具有重要意义。近期出现的亚波长非线性量子光源，例如GaP和LiNbO₃薄膜，得益于相位匹配约束的放宽和体积限制效应，展现出高维超纠缠、鲁棒纠缠抗退化等引人关注的特性。范德华（vdW）NbOCl₂晶体以其优异的光学非线性著称，已成为超薄量子光源的理想候选之一[Nature 613, 53 (2023)]。然而，NbOCl₂晶体由于其不利的非线性极化率张量，无法实现偏振纠缠。本文中，我们利用范德华体系固有的扭转堆叠自由度，展示了可调谐偏振纠缠和量子Bell态的制备。本研究不仅提供了一种新型可调谐偏振纠缠范德华光子对源，还为纳米尺度下量子光纠缠态的调控引入了新的自由度。
英文摘要：
Polarization entanglement holds significant importance for photonic quantum technologies. Recently emerging subwavelength nonlinear quantum light sources, e.g., GaP and LiNbO3 thin films, benefiting from the relaxed phase-matching constraints and volume confinement, has shown intriguing properties, such as high-dimensional hyperentanglement and robust entanglement anti-degradation. Van der Waals (vdW) NbOCl2 crystal, renowned for its superior optical nonlinearities, has emerged as one of ideal candidates for ultrathin quantum light sources [Nature 613, 53 (2023)]. However, polarization-entanglement is inaccessible in NbOCl2 crystal due to its unfavorable nonlinear susceptibility tensor. Here, by leveraging the twist-stacking degree of freedom inherently in vdW systems, we showcase the preparation of tunable polarization entanglement and quantum Bell states. Our work not only provides a new and tunable polarization-entangled vdW photon-pair source, but also introduces a new knob in engineering the entanglement state of quantum light at the nanoscale.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
