Ultrafast electron microscopy at the space and time limit

With advances in spatial resolution reaching the atomic scale, 2 and 3 dimensional (D) imaging in transmission electron microscopy (TEM) has become an essential methodology in various fields of research providing static structural information. Now it has become possible to integrate the ultrahigh temporal resolution (fourth dimension) to the 3D spatial resolution of TEM.1-5 Here, presented is the concept and recent application of time-resolved imaging in ultrafast electron microscopy (UEM), which made it possible to directly visualize a single gold nanorod (Au NR) undergoing plasmonic-acoustic vibration of sub-nanometer amplitude and picosecond period, upon femtosecond-pulsed light excitation for the first time.6 The unique integration of a direct electron detector with ultrafast electron microscopy7 in combination with the achievement of control over the quality of the pulsed electron beam enabled unprecedented spatiotemporal imaging of characteristic vibration of each nanostructure interfaced with a substrate, which has been veiled in ensemble measurements in solution