意大利里雅斯特大学Daniele Fausti团队实现了超快泵-探针相位随机断层扫描。2025年3月6日出版的《光：科学与应用》杂志发表了这项成果。

测量物质低能激发的波动是揭示材料非平衡响应本质的关键。光谱方法通过利用弱少光子探针与光物质相互作用的统计性质来解决物质波动问题，在这方面提供了一个有希望的前景。

研究组报道了超快相位随机断层扫描的首次实现，将泵浦探针实验与量子光学态断层扫描相结合，以测量复杂材料中的超快非平衡动力学。该方法利用具有相位随机相干超短激光脉冲的时间分辨多模外差检测方案，克服了相位稳定配置的局限性，并能够稳健地重建相位平均光学可观测值的统计分布。

通过测量α-石英中的相干声子响应，验证了该方法的有效性。通过以超快分辨率跟踪少光子探针的散粒噪声限制光子数分布的动力学，该结果为α-石英中声子态的非经典特征设定了上限，并为获取更复杂量子材料中的非平衡量子涨落提供了一条途径。

附：英文原文

Title: Ultrafast pump-probe phase-randomized tomography

Author: Glerean, Filippo, Rigoni, Enrico Maria, Jarc, Giacomo, Mathengattil, Shahla Yasmin, Montanaro, Angela, Giusti, Francesca, Mitrano, Matteo, Benatti, Fabio, Fausti, Daniele

Issue&Volume: 2025-03-06

Abstract: Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium response of materials. A promising outlook in this respect is offered by spectroscopic methods that address matter fluctuations by exploiting the statistical nature of light-matter interactions with weak few-photon probes. Here we report the first implementation of ultrafast phase randomized tomography, combining pump-probe experiments with quantum optical state tomography, to measure the ultrafast non-equilibrium dynamics in complex materials. Our approach utilizes a time-resolved multimode heterodyne detection scheme with phase-randomized coherent ultrashort laser pulses, overcoming the limitations of phase-stable configurations and enabling a robust reconstruction of the statistical distribution of phase-averaged optical observables. This methodology is validated by measuring the coherent phonon response in α-quartz. By tracking the dynamics of the shot-noise limited photon number distribution of few-photon probes with ultrafast resolution, our results set an upper limit to the non-classical features of phononic state in α-quartz and provide a pathway to access non-equilibrium quantum fluctuations in more complex quantum materials.

DOI: 10.1038/s41377-025-01789-y

Source: https://www.nature.com/articles/s41377-025-01789-y