X-ray Physics

The group of Ralf Röhlsberger uses X-rays from synchrotron radiation sources and X-ray lasers to study the structure and dynamics of condensed matter. The enormous brilliance of these sources, together with their well-defined polarization and temporal structure, enables access to previously unexplored areas of the nanocosm with unprecedented spatial-temporal resolution.

Research Areas

Examples for benefitting from such high resolution are growth processes of thin films and nanostructures, the formation of magnetic order in the self-organized growth of ultrathin layers on nanostructured templates, the coupling of magnetic metals through natively formed oxide layers, etc. To this end, the group is using the inner-shell electron resonance and the ultra-narrow nuclear resonance of Mössbauer isotopes.

In addition, due to their extremely small energy bandwidth, the nuclear resonances of Mössbauer nuclei are ideal probes for studying the fundamental properties of the collective light-matter interaction. An example is the collective version of the Lamb shift, which we could observe by embedding ultrathin layers of 57Fe Mössbauer nuclei, just a few nanometers thick, in an X-ray resonator. Such planar resonators allow very precise control of the light-matter interaction and enable the transfer of key phenomena of quantum optics to the hard X-ray regime. Examples are electromagnetically induced transparency, spontaneously generated coherences, spectral control of inner shell resonances and many others. These studies, partly made possible by high-purity X-ray polarimetry, open up fundamentally new applications in the field of non-linear X-ray optics for current and future X-ray laser sources.

Teaching Fields

Prof. Röhlsberger is teaching the course "Introduction to Modern X-Ray Science" for Master's degree students. 

Link to the Röhlsberger group at the University of Jena de