高相干超快电子源研究进展

发布时间：2018-07-17 20:06

【摘要】：以原子级时空分辨监测物质的动力学行为并从最根本层面理解自然界中的微观基本过程一直是飞秒物理、飞秒化学以及飞秒生物学研究的目标.时间分辨电子衍射巧妙地结合了抽运-探测技术和电子衍射技术,可实现直接"观察"和"冻结"类似的超快过程.然而,目前常用的超快电子探针的横向相干性仍受到电子源的初始尺寸、有效温度、能量弥散以及电子间固有库仑排斥的限制,还很难分辨化学和生物相关的复杂有机分子.近年来大量研究工作都集中在发展高相干的超短电子源,其不仅对时间分辨电子衍射研究起到推动作用,也将极大地促进超快电子显微镜、相干衍射成像以及叠层成像等的发展.本综述以相干性为主线,介绍了几种常用平面阴极光电发射源的研究进展,并从产生机理、独有特性和实验成果方面讨论了尖端发射源和冷原子电子源这两类新型的高相干超快电子源,最后对衍射技术的相干性发展和未来应用进行了展望.
[Abstract]:It is always the goal of femtosecond physics, femtosecond chemistry and femtosecond biology to monitor the dynamic behavior of matter by atomic space-time resolution and to understand the microscopic basic process in nature from the most fundamental level. Time-resolved electron diffraction (TREE) is a clever combination of pump-probe technique and electron diffraction technique, which can realize the direct "observation" and "freezing" similar ultrafast process. However, the transversal coherence of ultrafast electron probes is still limited by the initial size of electron source, effective temperature, energy dispersion and intrinsic Coulomb repulsion between electrons, and it is difficult to distinguish complex organic molecules related to chemistry and biology. In recent years, a great deal of research work has focused on the development of highly coherent ultrashort electron sources, which not only promote the study of time-resolved electron diffraction, but also greatly promote ultra-fast electron microscopy. The development of coherent diffraction imaging and laminated imaging. Taking coherence as the main line, this paper introduces the research progress of several commonly used planar cathode photoemission sources and its mechanism. Two new types of high coherent ultra-fast electron sources are discussed in terms of their unique characteristics and experimental results. Finally, the development and application of diffraction techniques in the future are prospected.
【作者单位】：中国科学院西安光学精密机械研究所超快诊断技术重点实验室;中国科学院大学;山西大学极端光学协同创新中心;西安工业大学光电工程学院;
【基金】：国家自然科学基金青年科学基金(批准号:11304374,61501363) 陕西省自然科学基础研究计划项目(批准号:2016JQ6013)资助的课题~~
【分类号】：TN10

【相似文献】