利用光谱分辨的Hong-Ou-Mandel干涉测量超越光子相干时间的阿秒延迟计量
Attosecond delay metrology beyond the photon coherence time with spectrally resolved Hong-Ou-Mandel interferometry
浏览论文内容
中文总结 AI 辅助
研究利用光谱分辨的Hong-Ou-Mandel干涉测量法，突破光子相干时间限制，实现单测量路径延迟传感，保持高灵敏度，对光子损失等具鲁棒性，无需重新校准，还测量了目标厚度，推动量子极限测量在实际传感应用发展。
中文摘要 AI 辅助
Hong-Ou-Mandel（HOM）干涉测量法能够在量子精度极限下进行延迟估计，但传统上局限于干涉光子相干时间内的路径差。本文中，我们利用光谱分辨的HOM干涉，在测量的Cramer-Rao界实现了单测量路径延迟传感，从而消除了光子相干窗口施加的传统动态范围限制，无需扫描校准。通过从光谱纠缠光子对的光谱干涉条纹中提取延迟信息，我们在超过光子相干时间两个数量级以上的工作范围内保持了近最优灵敏度。使用一百万个检测到的光子对，我们实现了20阿秒（6纳米）的时间延迟精度，而实时操作（1赫兹）产生330阿秒（100纳米）的精度。由于估计器依赖于条纹周期性而非绝对符合率，该方法对光子损失和干涉可见度变化具有内在鲁棒性，无需重新校准。作为实际演示，我们以纳米级精度测量了300微米透射目标的厚度。这些结果标志着朝着在实际传感应用中使用HOM干涉测量法进行量子极限测量迈出了重要一步。
英文摘要
Hong-Ou-Mandel (HOM) interferometry enables delay estimation at the quantum precision limit but is traditionally constrained to path differences within the coherence time of the interfering photons. Here, we demonstrate single-measurement path-delay sensing at the measurement Cramer-Rao bound using spectrally resolved HOM interference, thereby removing the conventional dynamic-range limitation imposed by the photon coherence window, with no scanning required for calibration. By extracting delay information from the spectral interference fringes of spectrally entangled photon pairs, we retain near-optimal sensitivity over an operational range exceeding the photon coherence time by over two orders of magnitude. Using one million detected photon pairs, we achieve a time-delay precision of 20 attosecond (6 nm), while real-time operation (at 1 Hz) yields 330 attosecond (100 nm) precision. Because the estimator relies on fringe periodicity rather than absolute coincidence rates, the method is intrinsically robust to photon losses and variations in interference visibility, eliminating the need for recalibration. As a practical demonstration, we measure the thickness of a 300 um transmissive target with nanometer-scale precision. These results mark a significant step towards deploying quantum-limited measurements in real-world sensing applications using HOM interferometry.
