Physicists of the Ludwig-Maximilians-Universität Munich and the Max Planck Institute of Quantum Optics shorten electron pulses down to 30 femtoseconds duration. This enables them to gain detailed insight into atomic motions in molecules.
Electrons are odd particles: they have both wave and particle properties. Electron microscopy has been taking advantage of this phenomenon for roughly a century now and grants us a direct insight into the fundamental components of matter: molecules and atoms.
For a long time, still images were provided, but for some years now scientists are making tremendous progress in short-pulse technology. They create beams of electron pulses, which can, due to their extremely short flashing, provide us with very sharp images of moving atoms and electrons. Nevertheless, some of the fastest processes still remained blurred.
A team of the Laboratory for Attosecond Physics (LAP) from the Ludwig-Maximilians-Universität (LMU) and the Max Planck Institute of Quantum Optics (MPQ) has now managed to shorten electron pulses down to 28 femtoseconds in duration. One femtosecond is a millionth of a billionth of a second (10 to the minus 15 s). Such shutter speeds enable us to directly observe the truly fundamental motions of atoms and molecules in solids, similar to stroboscopy.
Those who want to explore the microcosm and its dynamics need a high-speed camera for atoms. In order to sharply capture motions of such particles during a reaction, one needs to work with “shutter speeds” in the range of femtoseconds, since this is the speed of reactions in molecules and solids. Commonly, femtosecond-short shutter speeds are provided by short-pulse laser technology, but laser light is not able to spatially resolve atoms.
Scientists from the Laboratory for Attosecond Physics at LMU and MPQ have now succeeded in producing ultrashort electron pulses with a duration of only 28 femtoseconds. This is six times shorter than ever before. The length of the matter wave is only about eight picometers; one picometer is a trillionth of a meter (10 to the minus 12 m).
Due to this short wavelength, it is possible to visualize even single atoms in diffraction experiments. If such electrons meet a molecule or atom, they are diffracted into specific directions due to their short wavelength. This way they generate an interference pattern at the detector from which an atomic 3D-structure of the examined substance is reconstructed. If the pulses are short enough, a sharp snapshot of the movement is the result.
To test the new technique, the physicists applied their ultrashort electron pulses to a biomolecule in a diffraction experiment. It is planned to use those electron beams for pump-probe experiments: an optical laser pulse is sent to the sample, initiating a response. Shortly afterwards the electron pulses produce a diffraction image of the structure at a sharp instant in time.
A large amount of such snapshots at varying delay times between the initiating laser pulses and the electron pulses then results in a film showing the atomic motion within the substance. Thanks to the sub-atomic wavelength of the electrons, one therefore obtains a spatial image as well as the dynamics. Altogether this results in a four-dimensional impression of molecules and their atomic motions during a reaction.
„With our ultrashort electron pulses, we are now able to gain a much more detailed insight into processes happening within solids and molecules than before“, Dr. Peter Baum says. „We are now able to record the fastest known atomic motions in four dimensions, namely in space and time“. Now the physicists aim to further reduce the duration of their electron pulses. The shorter the shutter speed becomes, the faster the motions which can be recorded. The aim of the scientists is to eventually observe even the much faster motions of electrons in light-driven processes. Thorsten Naeser
A. Gliserin, M. Walbran, F. Krausz, P. Baum
Sub-phonon-period compression of electron pulses for atomic diffraction
Nature Communications, 27 October 2015, doi: 10.1038/ncomms9723
Dr. Peter Baum
Max Planck Institute of Quantum Optics
Am Coulombwall 1, 85748 Garching
Phone: +49 (0)89 / 289 - 14102
Prof. Dr. Ferenc Krausz
Chair of Experimental Physics,
Laboratory for Attosecond Physics
Director at Max Planck Institute of Quantum Optics, Garching, Germany
Phone: +49 (0)89 32 905 - 600
Telefax: +49 (0)89 32 905 - 649
Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics, Garching, Germany
Phone: +49 (0)89 32 905 -213
Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik
From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison
Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News