瑞士苏黎世联邦理工学院Hans Jakob Wörner团队近日研究了光电子频率分辨光门控法诺共振波包的相位分辨。该项研究成果发表在2025年7月1日出版的《自然—光子学》杂志上。
利用超快极紫外相干光源实现了能量接近法诺共振的结构化电子波包（EWP）的创建。然而，缺乏对EWP演化的直接实时观测和对EWP量子特性（包括振幅和相位）的全面重建。
研究组介绍并演示了一种全面的方法，用于直接测量和完整表征在原型法诺共振中创建的结构化EWP。由于其与频率分辨光学门控（FROG）的相似性，研究组将该方法命名为光电子FROG。相关的EWP由精心设计的极紫外泵浦脉冲启动。弱近红外激光场作为探测脉冲，在时域和频域对EWP的演变进行采样。
EWP的振幅和相位是通过基于短时傅里叶变换的时变重建算法获得的。鉴于该实验结果与时间依赖重建之间的高度一致性，研究组预计这种方法将广泛适用于研究复杂系统中的超快过程，特别是电子过程，以及在基本时间尺度上对这些系统的相干控制。
附：英文原文
Title: Resolving the phase of Fano resonance wave packets with photoelectron frequency-resolved optical gating
Author: Zhang, Pengju, Liang, Hao, Han, Meng, Trester, Joel, Ji, Jiabao, Rost, Jan Michael, Wrner, Hans Jakob
Issue&Volume: 2025-07-01
Abstract: The creation of structured electronic wave packets (EWPs) energetically close to Fano resonances has been achieved with ultrafast extreme ultraviolet coherent light sources. However, direct real-time observations of EWP evolution and full reconstructions of the quantum properties of EWPs, including both amplitude and phase, are lacking. Here we introduce and demonstrate a comprehensive approach for the direct measurement and complete characterization of structured EWPs created within a prototypical Fano resonance. Because of its analogy with frequency-resolved optical gating (FROG), we named the method photoelectron FROG. The correlated EWP is initiated by a carefully engineered extreme UV pump pulse. A weak near-infrared laser field, serving as a probe pulse, samples the evolution of the EWPs in the time domain, as well as in the frequency domain. The amplitude and phase of the EWPs are obtained via a time-dependent reconstruction algorithm based on a short-time Fourier transformation. Given the excellent agreement between our experimental results and time-dependent reconstructions, we expect this method to be broadly applicable to the study of ultrafast processes, especially electronic ones, in complex systems, as well as the coherent control of such systems on their fundamental timescales.
DOI: 10.1038/s41566-025-01715-z
Source: https://www.nature.com/articles/s41566-025-01715-z