Pushing the frontiers of attosecond technologies
In the past decade the possibility of generating attosecond pulses has made the observation of electronic processes on this very short time scale accessible, which has given us insight into the physics of electronic processes in atoms, molecules and even solids. In order to push this development further, e.g. into the direction of XUV-pump/XUV-probe experiments or 4D-imaging by attosecond X-ray diffraction, attosecond pulses with higher intensities as well as higher photon energies are required. While the physical mechanisms that would allow for such scaling are more and more understood, it is clear that in order to move from a proof-of-principle demonstration to a real infrastructure suitable for conducting systematic studies, a light source with unprecedented characteristics is needed: multi-octave bandwidth resulting in few-cycle pulse durations, multi-terawatt peak power at multi-kHz repetition rates, with a controlled waveform. At LEX Photonics such a system is being developed. It is based on optical parametric chirped pulse amplification pumped with picosecond pulses. The pumplaser is a diode-pumped Yb:YAG thin-disk system.
Laser-driven particle and brilliant photon sources
Our group focuses on the generation of novel particle and photon beams (the latter in close collaboration with F. Grüner) from laser driven sources. This on one hand involves the study and control of ultrahigh-intensity laser interaction with plasmas, and on the other hand drives the improvement of the drive laser pulse parameters through continuous laser development. The driver laser for these experiments is the ATLAS Ti:Sapphire laser, which is currently being upgraded from 100 TW to 300 TW peak power.
From laser-driven undulator sources towards table-top free-electron lasers
Encouraged by our laser-driven soft-X-ray undulator source and capitalizing on GeV-scale laser-plasma accelerators developed by the group of Stefan Karsch as well as on our miniature electron optics and cryogenic undulators, we are advancing laser-driven femtosecond undulator sources to hard-X-ray energies for time-resolved X-ray diffraction and spectroscopy. Our dream is to turn, one day, these devices to a compact free-electron laser.
Laser-driven proton beams for biomedicine
Laser-based high-energy proton/ion sources hold promise for a cost-effective approach to implementing particle cancer therapy. Irradiation of nanometer-thin diamond-like carbon (DLC) foils with ultrahigh-contrast multi-terawatt lasers results in highly enhanced proton yields and promise scalability to the energy range relevant for cancer treatment. We pursue the development of such a source and explore its suitability for future clinical applications.