In the past decade, four-dimensional electron microscopy (4D EM), which enables the direct observation of transient morphologies, structures and carrier dynamics of materials in real time and space, has attracted increasing interest to the research community due to its powerful capability in the interdisciplines of physics, material science, chemistry, and biology [1-2]. In this presentation, I will firstly give a brief introduction of the development of 4D-EM, several cutting-edge technologies, and the state-of-the-art of its applications. Then I will present our most recent development of two-color photon induced near field electron microscopy (PINEM) in 4D EM based on “photon gating” effect, which enhances the temporal resolution of 4D-EM by an order of magnitude . Such high temporal resolution enables visualizing the ultrafast electronic dynamics of a single nanostructure. Using this methodology, we reveal the nanoscale-femtosecond dielectric response of a single VO2冰球突破 nanowire in the insulator-to-metal phase transition. After that, I will talk about our development of liquid-phase 4D EM and its first application in imaging Brownian dynamics and photochemical reaction dynamics of nanoparticles in liquid on the nanometer-nanosecond time scale [4-6]. Both the translational and rotational dynamics of individual nanoparticles were imaged in both diffusion and ballistic regimes, and a full transition from diffusive to superdiffusive, and further to ballistic rotation was revealed with increasing the asymmetry of the particles. With increasing laser fluence, photoinduced photomorphic reaction dynamics such as agglomeration, coalescence, and fusion dynamics of plasmonic nanoparticles in liquid were directly unraveled. This advanced liquid-phase 4D EM opens a promising possibility for future study of numerous physical, chemical and biological dynamical processes in native environments. In the end, I will introduce the recent development of low-cost, laser-free 4D-EM and its application in visualization of electromagnetic wave propagation dynamics in high frequency miniature electronic devices at nanometer and picosecond scales, which extends the application of 4D EM to the field of electromagnetic dynamics in nanoscale electronic devices .
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 X. W. Fu et al., Nature Communications冰球突破 11(1), 1-11(2020).
 X. W. Fu et al., Science 355, 494-498 (2017).
 X. W. Fu et al., Science Advances冰球突破 3 (8), e1701160 (2017).
 X. W. Fu et al., Science Advances 4 (7), eaat3077 (2018).
 X. W. Fu et al., Science Advances 6 (40), eabc3456 (2020).
fuxuewen，nankaidaxuewulikexuexueyuanjiaoshou，boshishengdaoshi，haiwaiyinjinqingnianrencai，tianjinshijiechuqingnianjijinhuodezhe，nankaidaxue“baimingqingnianxuekedaitouren”，guojiazhongdianyanfajihuaqingnianxiangmushouxikexuejia。2014nianhuobeijingdaxueningjutaiwuliboshixuewei（daoshi：yudapengyuanshi），cengronghuobeijingshiyouxiuboshibiyesheng、beijingdaxueyouxiuboshibiyeshengheyouxiuboshilunwenjiang。xianhouzaimeiguojiazhouligongxueyuan（nuobeierjiangdezhuahmed zewailjiaoshouyanjiuzu）hemeiguobulukehaiwenguojiashiyanshi（yimei zhujiaoshouyanjiuzu）congshiyanjiugongzuo。2019nianshoupinyunankaidaxuewulikexuexueyuandanrenjiaoshou、bodao，qiantoujianlilenankaidaxuechaokuaidianzixianweijingshiyanshi。zhangqicongshi4dchaokuaidianzixianweijing、chaokuaiyinjiyingguangdengchaogaoshikongfenbiandianzichengxiangyutancejishukaifajiqizaidiweiliangzigongnengcailiaodejiegou、zailiuzijizixuandengdonglixuezhongdeyingyongyanjiu。zaiscience、science advances（3pian）、nature communications、advanced materials、pnas、acs nano（4pian）、nano lettersdengzhimingguojiqikanfabiaoxueshulunwenjin40pian，huoshouquanfamingzhuanli1xiang。yanjiuchengguoduocibei science、phys.org、physicsword、nanotechweb、advances in engineeringdengkexuemeitixuanweiyanjiuliangdianjinxingbaodao。