We investigate the femtosecond relaxation dynamics following the interaction of molecules and nanoparticles with ultrashort XUV and X-ray pulses. Our goal is to understand photoionization and fragmentation mechanisms of isolated systems at these wavelengths. We are currently following two pathways:
Evgenii Ikonnikov, Lorenz Drescher, Jochen Mikosch, Oleg Kornilov
One of the main mechanisms following the interaction of a molecule with a high energy photon is the removal of one electron resulting in the formation of a molecular cation that, depending on the photon energy, can further fragment. We use either broadband XUV pulses or individual harmonics obtained from a novel time-compensating monochromator to prepare excited cations and resolve in time the photoionization and fragmentation dynamics using single photon XUV ionization and photoion and photoelectron detection.
Oleg Kornilov, Bernd Schütte
Refraction of visible light is well known and is the underlying working principle of glasses, camera objectives and microscopes. We study and exploit refraction in the XUV range using dense atomic and molecular jets that form prisms or lenses. These deformable optical elements have a much higher transmission than typical reflective XUV mirrors or gratings. We further apply pump-probe schemes to control and exploit the transient refractive properties of atoms and molecules at XUV frequencies.