Researchers from Deutsches Elektronen-Synchrotron (DESY), University of Kiel and University of Hamburg have for the first time watched the quantum race of two electrons that are released from atoms during photoionization, that is, under the control of laser radiation.
Theoretical physicists Sebastian Bauch and Prof. Michael Bonitz of Kiel University provided a theoretical explanation of the measurements at the free-electron laser. (Photo & copyright: Stefanie Maack/ CAU)
Using a combination of a free-electron-laser and an ultra fast terahertz streak camera, the researchers have resolved the movement of the electrons during only 50 fs. The study results, reported in Physical Review Letters, will be helpful in the advancement of emerging free-electron-laser technology utilized in various scientific fields, from biology to physics.
Electron-electron interaction plays an important role in the properties of molecules and atoms, which are building blocks of all artificial systems and living organisms. Hence, it is crucial to understand the electronic processes in atoms to develop several future applications, from engineering to medicine.
The combination of an ultrafast streak camera and the free-electron laser FLASH at DESY in Hamburg is the key to watch the electron race. By precisely manipulating the timing of the two electromagnetic fields formed by the camera and the laser, the researchers reconstructed the electrons’ energy exchange and motion. By this way, the researchers were able to detect how the second electron called the Auger electron overtakes the first electron.
Professor Michael Bonitz reproduced the experimental findings using computer models at the Institute of Theoretical Physics and Astrophysics of Kiel University. Bonitz informed that after examining various potential justifications for the experimental results, Sebastian Bauch, a PhD student at the university, confirmed that the experiment indeed examined the quantum race of two electrons. The study findings provide important insights about critical properties of the laser pulse used.