张量工程化范德华NbOCl2共振超表面用于偏振纠缠贝尔态产生

中文摘要 AI 辅助

偏振纠缠光子对是量子信息技术的关键资源，然而实现具有内在可控纠缠的紧凑型光源仍具挑战性。范德华（vdW）非线性材料如NbOCl2为量子光产生提供了原子级薄平台，但其作为天然材料的固有晶体各向异性限制了可访问的量子态。在此，我们开发了一种基于NbOCl2的共振范德华非线性超表面，利用其固有光学各向异性来工程化偏振相关的非线性响应。各向异性光学色散使得能够选择性操控共振模式，导致沿c轴的非线性响应增强三个数量级。通过进一步定制这些共振模式，我们在正交偏振通道之间重新分配有效二阶非线性磁化率张量，平衡沿b轴和c轴的自发参量下转换路径。这使得偏振纠缠光子产生具有高达92%的测量保真度。我们的工作确立了超表面使能的非线性光学工程作为增强和控制vdW材料中量子光产生的策略，为可扩展量子光子平台提供了途径。

英文摘要

Polarization-entangled photon pairs are essential resources for quantum information technologies, yet realizing compact sources with intrinsically controllable entanglement remains challenging. Van der Waals (vdW) nonlinear materials such as NbOCl2 provide atomically thin platforms for quantum light generation, yet their native crystalline anisotropies as natural materials impose limitations on accessible quantum states. Here, we develop a resonant vdW nonlinear metasurface based on NbOCl2 that exploits its intrinsic optical anisotropy to engineer polarization-dependent nonlinear responses. The anisotropic optical dispersion enables selective manipulation of resonant modes, resulting in a three-order-of-magnitude enhancement of the nonlinear response along the c axis. By further tailoring these resonant modes, we redistribute the effective second-order nonlinear susceptibility tensor between orthogonal polarization channels, balancing the spontaneous parametric down-conversion pathways along the b and c axes. This enables polarization-entangled photon generation with a measured fidelity of up to 92%. Our work establishes metasurface-enabled nonlinear optical engineering as a strategy for enhancing and controlling quantum light generation in vdW materials, providing a pathway toward scalable quantum photonic platforms.

发表机构

• CAS Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology（中国科学院纳米科技标准化与计量重点实验室，国家纳米科学中心）
• Frontiers Science Center for New Organic Matter, Tianjin Key Lab for Rare Earth Materials and Applications, Renewable Energy Conversion and Storage Center (RECAST), School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University（前沿科学中心新有机物质，天津市稀土材料与应用重点实验室，可再生能源转换与存储中心（RECAST），南开大学材料科学与工程学院，先进材料国家研究院）
• CAS Key Laboratory of Quantum Information, University of Science and Technology of China（中国科学院量子信息重点实验室，中国科学技术大学）
• School of Materials Science and Engineering, Peking University（北京大学材料科学与工程学院）
• School of Materials Science and Engineering, Nanyang Technological University（南洋理工大学材料科学与工程学院）
• School of Electrical and Electronic Engineering, Nanyang Technological University（南洋理工大学电气与电子工程学院）
• University of Chinese Academy of Sciences（中国科学院大学）
• Hefei National Laboratory, University of Science and Technology of China（合肥国家实验室，中国科学技术大学）
• Beijing Key Laboratory of Advanced Micro- and Nanoscale Light Source Materials and Devices, Peking University（北京先进微纳光源材料与器件重点实验室，北京大学）

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