22-Aug-2011 - Julius-Maximilians-Universität Würzburg

High-tech microscope measures electron oscillations

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 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.

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.

The research team and its sponsors

The teams of Professor Martin Aeschlimann (Kaiserslautern), Tobias Brixner (Würzburg) and Walter Pfeiffer (Bielefeld) presented their new analysis method on 11 August 2011 in "Science". The German research association (DFG) has supported the project of the three research teams within the scope of its priority program "Ultrafast Nano-Optics".

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". 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.

  • Martin Aeschlimann et al.; „Coherent Two-Dimensional Nanoscopy"; Science
Facts, background information, dossiers
More about Uni Würzburg
  • News

    Triangular Honeycombs: Physicists design novel quantum material

    Researchers from the Würzburg-Dresden Cluster of Excellence ct.qmat–Complexity and Topology in Quantum Matter – have conceived and realized a new quantum material: "Indenene". Consisting of a single layer of the chemical element Indium, indenene enriches the family of the so-called topologi ... more

    New Coating for Plastics to Fight Bacteria off

    The start-up Flux Polymers, which has its roots at the University of Würzburg, offers a simple and easy solution to keep plastic surfaces free of bacteria. Recently, it has found an investor and can now start its operational business. In clinics and medical practices, it is crucial to work ... more

    Team tracks real-time molecular motions

    The efficiency of solar cells can be significantly increased with a certain physical effect. A research team has now observed in detail for the first time how molecular movements influence this effect. Researchers from the Fritz Haber Institute (FHI) in Berlin, the Max Planck Institute for ... more

More about TU Kaiserslautern
More about Uni Bielefeld
  • News

    Tiny nanoparticles improve charge transport

    Three-dimensional topological insulators are materials that can conduct electric current without resistance—but only on their surface. However, this effect is difficult to measure. This is because these materials usually have little surface area in relation to their volume, which means thei ... more

    Graphene: Everything under control

    How can large amounts of data be transferred or processed as quickly as possible? One key to this could be graphene. The ultra-thin material is only one atomic layer thick, and the electrons it contains have very special properties due to quantum effects. It could therefore be very well sui ... more

    Spin current from heat

    Electronic devices such as computers generate heat that mostly goes to waste. Physicists at Bielefeld University have found a way to use this energy: They apply the heat to generate magnetic signals known as 'spin currents'. In future, these signals could replace some of the electrical curr ... more