Single photons exhibit inherently quantum and unintuitive properties such as the Hong-Ou-Mandel effect, demonstrating their bosonic and quantized nature, yet at the same time may correspond to single excitations of spatial or temporal modes with a very complex structure. Those two features are rarely seen together. Here we experimentally demonstrate how the Hong-Ou-Mandel effect can be spectrally resolved and harnessed to characterize a complex temporal mode of a single-photon—a zero-area pulse—obtained via a resonant interaction of a terahertz-bandwidth photon with a narrow gigahertz-wide atomic transition of atomic vapor. The combination of bosonic quantum behavior with bandwidth-mismatched light-atom interaction is of fundamental importance for deeper understanding of both phenomena, as well as their engineering offering applications in characterization of ultrafast transient processes.

中文翻译：

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零面积脉冲的单光子全息图

单光子表现出固有的量子和非直观特性，例如洪欧曼德尔效应，证明了它们的玻色子和量子化性质，但同时可能对应于具有非常复杂结构的空间或时间模式的单一激发。这两个功能很少一起出现。在这里，我们通过实验证明了 Hong-Ou-Mandel 效应如何能够被光谱解析并用于表征单光子的复杂时间模式 - 零区域脉冲 - 通过太赫兹带宽光子与窄带的共振相互作用获得原子蒸气的千兆赫兹宽原子跃迁。玻色子量子行为与带宽不匹配的光原子相互作用的结合对于深入理解这两种现象至关重要，