The free-electron X-ray lasers and the atomic X-ray lasers are suitable for a variety of different tasks, but they also work very well together: their X-ray bursts have different wavelengths, creating a two-colour X-ray laser in which both pulses are perfectly synchronised. “We can use this to start a process with one pulse – such as a chemical reaction or an excitement or a structural change in a solid state – and to take a photograph of this process with the pulse of the other colour after a certain period of time,” explains Nina Rohringer. If one of the pulses is directed via a precisely defined detour, it can be delayed by a specified short period of time, to take a photograph of various stages of a chemical reaction. As both pulses are generated simultaneously, this period of time can be precisely determined.
Rohringer would now like to develop the atomic X-ray laser further at the Hamburg-based CFEL: “We are investigating, for example, how we can achieve even higher energies and whether it is possible to use molecules, such as oxygen, instead of neon atoms, as a laser medium.” This could result in an X-ray laser that generates short pulses of sharply defined wavelengths and in this way covers a broader range of wavelengths. This is a prerequisite for conducting spectroscopic studies, which are only possible using light from a variable wavelength.
The LCLS (Linac Coherent Light Source) X-ray laser is a major research facility funded by the US Department of Energy at the SLAC Accelerator Laboratory in California. LCLS is the world’s first free-electron laser for hard X-rays and allows researchers to observe atomic-scale details and ultra-short processes in the nanoworld. LCLS facilitates pioneering research in physics, chemistry, structural biology, energy research and numerous other fields.
The Center for Free-Electron Laser Science (CFEL) at the Hamburg-Bahrenfeld research campus is a joint venture between Deutsches Elektronen-Synchrotron DESY, the Max Planck Gesellschaft and the University of Hamburg. It conducts research on free-electron lasers (FEL). These innovative light sources, based on linear particle accelerators, allow researchers to observe Nature live at an individual molecular and atomic scale. Leading researchers from a variety of disciplines come together under the CFEL roof to cooperate on interdisciplinary topics. Currently, more than 140 CFEL employees are divided into five divisions and two Advanced Study Groups with an annual budget of a total of more than EUR 10 million. For more information on CFEL please visit the Center's website at http://www.cfel.de.