Scalable integrated single-photon sources are critical for quantum photonics and can enable applications such as high-speed quantum communication and quantum information processing. Ideally, to establish a scalable platform, such single-photon sources require emission speed-up and efficient extraction in a single architecture, especially for extremely large extraction decay rates. However, this goal remains elusive so far. Current approaches to enhance photon extraction decay rates for plasmonic nanostructures, including hybrid antennas, plasmonic cavities, photonic hypercrystals, and metamaterials, are either dependent on hybrid plasmonic modes, which suffer from structural complexity, or limited by poor outcoupling efficiency. Here, we propose a novel paradigm—spatial topological transition in the architecture of feasible metamaterial structure (e.g., an array of silver flat-topped conical rods), which can strongly enhance the photon extraction decay rate of quantum emitters. The underlying physics relies on the emerging unique feature of spatial topological transitions due to the transition from elliptical to hyperbolic iso-frequency contours in a single spatially varying metamaterial. Hence, the supported high-k eigenmodes in the metamaterial can now become momentum-matched with the radiative modes. More importantly, due to the existence of elliptical and hyperbolic zones, it is possible to allow for the realization of an extremely large value of extraction decay rate. Our results thus represent a crucial step for the integration of single-photon sources into photonic quantum networks and quantum information applications.

中文翻译：

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通过空间拓扑转变的单光子提取

可扩展的集成单光子源对于量子光子学至关重要，可以实现高速量子通信和量子信息处理等应用。理想情况下，为了建立可扩展的平台，此类单光子源需要在单一架构中实现发射加速和高效提取，特别是对于极大的提取衰减率。然而，这一目标至今仍难以实现。目前提高等离激元纳米结构光子提取衰减率的方法，包括混合天线、等离激元腔、光子超晶体和超材料，要么依赖于结构复杂的混合等离激元模式，要么受到较差的外耦合效率的限制。在这里，我们提出了一种新的范式——在可行的超材料结构（例如银平顶圆锥棒阵列）的架构中进行空间拓扑转变，它可以大大提高量子发射器的光子提取衰减率。基础物理学依赖于空间拓扑转变的新兴独特特征，这是由于单个空间变化的超材料中从椭圆形等频轮廓到双曲等频轮廓的转变。因此，超材料中支持的高 k 本征模式现在可以与辐射模式动量匹配。更重要的是，由于椭圆和双曲线区域的存在，可以实现极大的提取衰减率值。因此，我们的结果代表了将单光子源集成到光子量子网络和量子信息应用中的关键一步。