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图1 Graphical abstract

1. 回顾了电子-晶格相互作用动力学的发展历程，阐明了超快电子成像的必要性和优势；

2.分析了3种典型超快电子成像方法的原理及装置，即，时间分辨光发射电子显微镜（time-resolved photoemission electron microscopy, TR-PEEM）、扫描超快电子显微镜（scanning ultrafast electron microscopy, SUEM）和超快透射电子显微镜（ultrafast transmission electron microscopy, UTEM），并总结了光与电子相互作用、载流子输运和弛豫、电子晶格耦合和晶格振荡等方面的典型成果；

3.展望了超快电子成像发展趋势，指出发展更高时空分辨能力的超快电子成像方法在多场耦合下的复杂动力学研究中具有广阔前景。

Highlights:

1. The historical development of electron-lattice interaction dynamics is reviewed and the necessity and advantages of ultrafast electron imaging are elucidated.

2. The principles and apparatus of three typical ultrafast electron imaging methods (TR-PEEM, SUEM, UTEM) are analyzed, and some key achievements in the areas, such as light-electron interaction, charge carrier transport and relaxation, electron-lattice coupling, and lattice oscillations, are summarized.

3. The future trends in ultrafast electron imaging are outlined, proposing the development of ultrafast electron imaging methods with higher spatiotemporal resolution, and emphasizing the promising prospects in studying complex dynamics under multi-field coupling.

电子-晶格的结构演化决定物质的宏观性质。探索其动力学过程有助于理解物质的宏观物理、化学和生物特性，推动应用技术的发展。电子-晶格的相互作用特征时间在飞秒至皮秒量级，线性和非线性过程并存，且伴随纳米尺度的空间演化。泵浦探测方法能够满足探测的时间分辨要求，但存在由光学衍射极限导致空间分辨率不足的缺陷。为提升电子-晶格动力学过程的空间分辨能力，通过电子束成像结合高时空分辨率脉冲激光的方法近年来取得了不少突破。为提升电子-晶格动力学过程的空间分辨能力，通过电子束成像结合高时空分辨率脉冲激光的方法近年来取得了不少突破，成为了基础研究和应用验证的重要手段。然而，不同物质本征状态及超快过程特性导致成像策略发生变化，现有的研究更关注单一成像方法或单一物质的进展。在广泛的体系中，如何适配成像策略与研究对象，从而解决电子-晶格动力学中的核心问题成为了关键。

北京理工大学姜澜教授团队在《国际机械系统动力学学报（英文）》（International Journal of Mechanical System Dynamics, IJMSD）发表题为“Probing electron and lattice dynamics through ultrafast electron microscopy: Principles and applications”的综述。该文详述了电子-晶格动力学的时空特性，提出了使用超快电子进行高时空分辨成像是解析纳米尺度超快电子-晶格演化关键的观点。并根据不同的成像原理和应用场景，介绍了时间分辨光发射电子显微镜（TR-PEEM）、扫描超快电子显微镜（SUEM）及超快透射电子显微镜（UTEM）3种典型的超快电子成像方法。内容涉及：（1）使用TR-PEEM研究近场增强和退相干性质的关联性，以及对表面等离激元传播过程成像；（2）使用SUEM揭示硅、InGaN、单晶中的载流子弛豫/扩散动力学；（3）使用UTEM解析过渡金属二卤化物中的晶格振动，金属中的马氏体相变及纳米颗粒的受激团聚现象。该文以电子-晶格动力学的研究为目标，系统总结了超快电子成像的原理、方法及关键技术，对前沿基础科学和国家重大应用中的超快研究需求具有重要指导作用。

Abstract：Microscale charge and energy transfer is an ultrafast process that can determine the photoelectrochemical performance of devices. However, nonlinear and non-equili-brium properties hinder our understanding of ultrafast processes; thus, the direct imaging strategy has become an effective means to uncover ultrafast charge and energy transfer processes. Due to diffraction limits of optical imaging, the obtained optical image has insufficient spatial resolution. Therefore, electron beam imaging combined with a pulse laser showing high spatial-temporal resolution has become a popular area of research, and numerous breakthroughs have been achieved in recent years. In this review, we cover three typical ultrafast electron beam imaging techniques, namely, time-resolved photoemission electron microscopy, scanning ultrafast electron microscopy, and ultrafast transmission electron microscopy, in addition to the principles and characteristics of these three techniques. Some outstanding results related to photon-electron interactions, charge carrier transport and relaxation, electron-lattice coupling, and lattice oscillation are also reviewed. In summary, ultrafast electron beam imaging with high spatial-temporal resolution and multidimensional imaging abilities can promote the fundamental under-standing of physics, chemistry, and optics, as well as guide the development of advanced semiconductors and electronics.