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Two-Dimensional Nanoscopy: Measuring Electron Oscillations
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Researchers from Bielefeld, Kaiserslautern and Würzburg have developed a novel high-tech microscope: It magnifies objects a million times and shows movements with a retardation of one million billion times. The results were published in Science.
The new technology allows tracking extremely fast processes in miniature objects - with an unparalleled spatial and temporal resolution. "For the first time we were able to determine the duration of electron oscillations in a single nano structure", says Professor Tobias Brixner of the Institute for Physical and Theoretical Chemistry of the University of Würzburg, Germany.
The analyses have shown that the collective electron movement after exciting a silver nano structure with light lasts up to 20 times longer in certain places than was thought. The duration of electron oscillations is of interest not only for basic research. It also has a significant influence on the efficiency of energy transport processes as occur, for instance, in photovoltaic cells or during the photosynthesis of plants.
"Our new method will allow us in the future to track very fast processes in many natural and artificial nano-structured materials", the scientists explain.
Electron microscopy combined with laser flashes
How did the cooperation partners accomplish this success? They combined the advantages of an electron microscope with the excitation of ultra-short laser flashes and the high time resolution that can be achieved by this. This enables them to detect structures ten times smaller than would be possible using optical microscopes. The progress of the object properties can thus be followed with the extremely high time resolution of a few femtoseconds - an inconceivably short period of time during which a jet plane travels a distance smaller than the diameter of an atom", as Professor Brixner compares.
In order to be able to track ultrafast processes in the microcosm, the researchers use a complex sequence of ultra-short laser pulses which experts refer to as "coherent two-dimensional nanoscopy".
Imaging & Microscopy Issue 4 as free epaper or pdf download
The physicists and physical chemists finally accomplished their goal by developing a new sequence of laser pulses and the proof of the electrons emitted in this process.
Original publication:
Martin Aeschlimann, Tobias Brixner, Alexander Fischer, Christian Kramer, Pascal Melchior, Walter Pfeiffer, Christian Schneider, Christian Strüber, Philip Tuchscherer, Dmitri V. Voronine: Coherent Two-Dimensional Nanoscopy, Science, August 11, 2011, DOI 10.1126/science.1209206
Authors:
Robert Emmerich
Keywords: Electron Microscopy Electron Oscillations lasers Microscopy nanoscopy the University of Würzburg Tobias Brixner Ultra-short Laser Flashes
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