A paper written by Drs. Yuya Morimoto and Peter Baum of the Laboratory for Attosecond Physics, which is jointly run by LMU Munich and the Max Planck Institute for Quantum Optics, is featured on the cover of the March 2018 issue of Nature Physics. Its authors have developed a novel form of electron microscopy, which allows light-matter interactions to be observed in real time at atomic resolution. The new method thus makes it possible to visualize atomic processes as they unfold in space and time. In the experiments described in the report, the Munich researchers make use of the oscillating electric field of laser light to ‘chop’ an electron beam into a sequence of attosecond pulses. By focusing the pulse trains on a silicon crystal, they were able to observe, in real time, how the electromagnetic waveform propagates within the crystal, as well as the relationship between the diffraction of the electrons by atoms in the crystal and the phase of the optical field.
The cover picture shows a superimposition of data obtained from a set of time-delayed measurements, and reveals how the Bragg-reflections that make up the diffraction pattern change when varying the delay of the light-cycle excitation.