research — Seeing how atoms and electrons in a material respond to external stimuli can give scientists insight into mysteries of solid-state physics, like how high temperature superconductors and other exotic materials work. Short pulses of electrons can be used to film such motions. When an electron scatters from a crystal, due to its quantum mechanical wave-like properties, it interferes with itself to create a diffraction pattern. By recording these patterns, researchers can see the atomic and electronic structure of the material, resolving details smaller than the size of an atom. Short electron pulses are, however, difficult to generate, because electrons carry a charge and move slower than the speed of light. In particular, electron pulse technology is still far away from the time resolution required to see the motions of electrons inside a material. Now, a team headed by Dr. Peter Baum and Prof. Ferenc Krausz from the Laboratory for Attosecond Physics (LAP), the Ludwig-Maximilians University (LMU) and the Max- Planck Institute of Quantum Optics (MPQ) has succeeded in developing a new technique for controlling ultrafast electron pulses (see: ‘Movies out of the Microcosm’). While, to date, microwave technology has been used to control electron pulses, the LMU and MPQ researchers have for the first time used optically-generated terahertz radiation. Using the new technique, the physicists have succeeded in significantly shortening electron pulses. This terahertz method offers the potential of visualizing not only atoms but also electrons in motion.