In the atto-atto group at the Max-Born-Institut (MBI) in Berlin we are studying and controlling ultrafast dynamics using extreme-ultraviolet (XUV) pulses from the attosecond to the femtosecond regime.

All-attosecond pump-probe spectroscopy

Our focus lies on the development and application of attosecond-pump attosecond-probe spectroscopy (APAPS), which has substantial advantages compared to conventional attosecond techniques. On one hand, the attosecond pulses in both the pump and the probe step allow for specific excitation from valence and core levels. On the other hand, the use of strong laser fields can be avoided which often mask or change the dynamics of interest. Recent highlights include the attosecond investigation of XUV multi-photon multi-electron ionization and the the compact realization of all-attosecond pump-probe spectroscopy.

Novel high-harmonic generation schemes

For our research, we are developing novel HHG schemes. Recent highlights include the demonstration of HHG in a strongly overdriven regime, the realization of a compact setup for the generation of intense XUV pulses, and the development of a long HHG beamline used for the highly nonlinear ionization of atoms.

Spectral and temporal compression schemes

In the XUV region, temporal and spectral compression are very difficult to achieve. Recently, we have developed a spectral compression scheme in the XUV range, relying on a novel phase-matching scheme in four-wave mixing.

Furthermore, we are developing novel post-compression schemes in the NIR and visible spectral range to generate few-cycle high-energy laser pulses.

XUV refractive optics

We develop and apply refractive lenses and prisms for extreme-ultraviolet (XUV) light. In contrast to the visible regime where glass lenses and prisms are used, we generate atomic or molecular jets to focus or spectrally disperse XUV beams. See our publication in Nature for more information: Extreme-ultraviolet refractive optics