Photon gating in four-dimensional ultrafast electron microscopy

Mohammed T. Hassan, Haihua Liu, John Spencer Baskin, Ahmed H. Zewail

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Ultrafast electron microscopy (UEM) is a pivotal tool for imaging of nanoscale structural dynamics with subparticle resolution on the time scale of atomic motion. Photon-induced near-field electron microscopy (PINEM), a key UEM technique, involves the detection of electrons that have gained energy from a femtosecond optical pulse via photon-electron coupling on nanostructures. PINEM has been applied in various fields of study, from materials science to biological imaging, exploiting the unique spatial, energy, and temporal characteristics of the PINEM electrons gained by interaction with a "single" light pulse. The further potential of photon-gated PINEM electrons in probing ultrafast dynamics of matter and the optical gating of electrons by invoking a "second" optical pulse has previously been proposed and examined theoretically in our group. Here,we experimentally demonstrate this photon-gating technique, and, through diffraction, visualize the phase transition dynamics in vanadium dioxide nanoparticles. With optical gating of PINEM electrons, imaging temporal resolution was improved by a factor of 3 or better, being limited only by the optical pulse widths. This work enables the combination of the high spatial resolution of electron microscopy and the ultrafast temporal response of the optical pulses, which provides a promising approach to attain the resolution of few femtoseconds and attoseconds in UEM.

Original languageEnglish (US)
Pages (from-to)12944-12949
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 20 2015
Externally publishedYes


  • Attosecond electron microscopy
  • Optical-gated electron pulse
  • Photon-electron gating
  • Photon-induced near-field electron microscopy
  • Time-resolved PINEM

ASJC Scopus subject areas

  • General


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