Progress in the development of scanning ultrafast electron microscopy

ORAL

Abstract

In recent years, ultrafast electron microscopy (UEM) has been developed as a technique that enables time-dependent imaging of structural dynamics in the condensed phase. The central concept involves the usage of a femtosecond or nanosecond laser pulse to initiate dynamical changes in the specimen, and a second light pulse that generates an electron packet as the probe for detection. In UEM, the electron pulses are accelerated typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy (SUEM) using a field-emission-source configuration, which is different from UEM's. Scanning of pulses is made with only one or a few electrons per pulse, thus achieving imaging still in ten(s) of seconds and without much of the space-charge effect between electrons. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in-situ 4D imaging and with environmental capability.

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Authors

  • Ding-Shyue Yang

    California Institute of Technology

  • Omar Mohammed

    California Institute of Technology

  • Andreas Bill

    Photonics CoE, Sciprint.org, LLNL, OSU, Imperial College London, General Atomis, UCSD, University of Milan, Instituto Superior Technico, University of Alberta, US Dept. of Agriculture, Agriculture Research Service, Parlier, CA, Dept. of Chemistry, California State University, Fresno, Dept. of Physics, California State University, Fresno, Weizmann Institute of Science, Stanford University, University of Connecticut, Storrs, UC Irvine, University of Missouri-Kansas City, California Institute of Technology, Ulm University, TU Darmstadt, UC Berkeley, GSFC, University of Regenberg, Germany, Lawrence Livermore National Laboratory, Clarendon Laboratory, Oxford, University of California, Los Angeles, Gesellschaft fuer Schwerionenforschung (GSI), Laboratoire pour l'Utilisation des Lasers Intenses, PSFC, MIT, University of California, Santa Barbara, Process Measurements Division, National Institute of Standards and Technology, Gaithersburg, MD, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, Division of Chemistry, California Institute of Technology, Pasadena, CA, Department of Physics, Fars Science and Research Center, Islamic Azad University, Texas A\&M University-Commerce, California State University, Long Beach, Materials Department, University of California Santa Barbara