Next-Gen Ultrafast Optical Fiber-Based Electron Gun to Reveal Atomic Motions During Transition State

Next-Gen Ultrafast Optical Fiber-Based Electron Gun to Reveal Atomic Motions During Transition State

Ultrabright electron pulses and a streak camera will enable researchers to directly observe and capture atomic motions at surfaces and interfaces in real time.

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By AIP News Staff

WASHINGTON, D.C., Oct. 9, 2018 – One of the most enduring "Holy Grail" experiments in science at atomic motions during structural changes. This prospect underpins the whole field of chemistry because of a chemical process occurs during a transition state – the point of no return.

What makes that transition to a different state of the art, how does it work?

Now in the newspaper Applied Physics Letters, from AIP Publishing, researchers at the Max Planck Institute for the Structure and Dynamics of Matter are reporting "ultrabright" electron sources with sufficient brightness to literally light up atomic motions in real time – at a time scale of 100 femtoseconds, making these sources particularly due to atomic motions occur in that window of time.

After the first atomic movies of phase transitions in bulk thin films using high-energy (100 kilovolt) electron bunches, the researchers wondered if they could achieve atomic resolution of surface reactions a better understanding of surface catalysis.

So they devised a low-energy (1-2 kilovolt) time-resolved electron diffraction concept of using fiber optics for miniaturization and the ability to stretch the electron pulse, then apply streak camera technology to obtain subpicosecond temporal resolution – a difficult feat within the low-electron energy regime.

"The first atomic movies use a stroboscopic approach to an old 8-millimeter camera, frame by frame, in which a laser excitation pulse triggers the structure, then an electron pulse is used to light the atomic positions," said co-author Dwayne Miller. "We believed that a streak camera could be deliberately stretched electron pulse. It solves the problem of low electron numbers and improves image quality. "

Of the myriad possible nuclear configurations, the group discovered that the system collapses to just a few key features that can not be reduced. "We see it directly with the first atomic movies of ring closing, electron transfer and bond breaking," said Miller.

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The article "Optical fiber driven low energy electron gun for ultrafast streak detection," is authored by Chiwon Lee, Gunther H. Kassier and R. J. Dwayne Miller. It appears in the journal Applied Physics Letters (DOI: 10.1063 / 1.5039737) and can be accessed at http://aip.scitation.org/doi/full/10.1063/1.5039737.

ABOUT THE JOURNAL

Applied Physics Letters concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on physics phenomena related to all branches of science, engineering, and modern technology. See http://apl.aip.org.