We demonstrated an ultrafast time-resolved measurement method operating at the single-photon level and employing a two-color comb-based asynchronous optical sampling (ASOPS) setup. We harnessed the two-color ASOPS photon counting approach to achieve long-term averaging of the ultralow intensity signal with a synchronized optical trigger signal, which minimizes residual timing jitter between the two combs. A pulse-width limited picosecond cross-correlation signal was successfully obtained with a power level of <1 photon/pulse. This approach enables the thorough study of ultrafast time-resolved detection of entangled photon pairs, quantum mechanical correlations in the time-frequency domain and finds wide use in optical quantum technology.

中文翻译：

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使用基于双色双梳的异步线性光学采样进行单光子级超快时间分辨测量

我们演示了一种在单光子水平上运行并采用基于双色梳的异步光学采样（ASOPS）设置的超快时间分辨测量方法。我们利用双色 ASOPS 光子计数方法，通过同步光触发信号实现超低强度信号的长期平均，从而最大限度地减少两个光梳之间的残余定时抖动。成功获得脉冲宽度受限的皮秒互相关信号，其功率水平<1光子/脉冲。这种方法能够对纠缠光子对的超快时间分辨检测、时频域中的量子力学相关性进行深入研究，并在光量子技术中得到广泛应用。