高时空分辨透射电子显微镜发展与应用

Development and Application of Ultrafast Transmission Electron Microscope

超快透射电子显微镜(Ultrafast Transmission Electron Microscopy,UTEM)集成了高空间和时间分辨率,使直接可视化材料的动力学过程成为可能。本文主要介绍UTEM系统的发展和应用:基于泵浦-探测(Pump-Probe)技术的UTEM系统的基本原理;目前全世界范围内几个主要机构的UTEM系统;中科院物理所李建奇研究员团队自主研发的基于热发射电子枪的第一代UTEM系统和基于场发射电子枪(Field Emission Electron Gun,FEG)的第二代UTEM系统;UTEM系统中的超快实空间成像、超快电子衍射(Ultrafast Electron Diffraction,UED)、时间分辨电子能量损失谱(Time Resolved Electron Energy Loss Spectrum,TREELS)相结合的最新研究成果,例如晶格和电子动力学、相变动力学、光诱导近场电子显微镜(Photon-Induced-Near-Field Electron Microscopy,PINEM)等。目前,超快电镜已经成为研究微纳尺度下非平衡态动力学过程的独一无二的工具。未来,随着电子脉冲质量和TEM的空间分辨率不断提高,有望实现具有更高时空分辨能力的UTEM系统。中国对UTEM的研究投入较少,当前应抓住UTEM的发展机遇,高效推进UTEM领域的关键技术、核心部件和重大产品创新和产业发展,将科技创新和产业发展紧密衔接。

Ultrafast Transmission Electron Microscopy(UTEM)integrates high spatial and temporal resolution,making it possible to directly visualize the dynamic processes of materials.This paper mainly introduces the development and application of UTEM system,including:the basic principle of UTEM system based on Pump-Probe technology;the current UTEM systems in several major institutions around the world;the first generation UTEM system based on thermal emission electron gun and the second generation UTEM system based on field emission electron gun(FEG)independently developed by Li Jianqi’s team from Institute of Physics,Chinese Academy of Sciences;the latest research achievements in UTEM system combined with ultrafast real space imaging,ultrafast electron diffraction(UED)and time-resolved electron energy loss spectrum(TREELS),such as lattice and electron dynamics,phase transition dynamics,photon-induced near-field electron microscopy(PINEM),etc.At present,UTEM has become a powerful tool for the study of non-equilibrium dynamics at micro-nano scale.In the future,as electron pulse quality and spatial resolution of TEM continue to improve,UTEM is expected to achieve higher spatial and temporal resolution.China has invested relatively less in the research of UTEM.At present,it is necessary to seize the development opportunity of UTEM,effectively promote the innovation and industrial development of key technologies,core components and major products in the field of UTEM,and closely link scientific and technological innovation with industrial development.