The building blocks of matter, electrons, and atomic nuclei, relentlessly move on a time scale much faster than what our senses manage to grasp. Their spatial distribution and evolution over time dictate a large portion of the chemical and physical properties of organic and inorganic substances. Detecting and understanding such ultrafast evolution is the very complex task pursued by time-resolved spectroscopy.
As a photographer that “freezes” a fast object by taking a picture with a short and bright flash, time-resolved spectroscopy probes matter with ultrashort bunches of photons and detects how it responds on the same time scale. Nuclei move on temporal scales of tens to hundreds of femtoseconds (1 femtosecond = 10-15 s) hence their evolution can be captured using femtosecond light pulses. Laser sources providing such pulses exist since the ‘80s and enabled the development of femtochemistry, i.e. the discipline studying chemical reactions on their natural temporal scale. However, the other constituents of matter – electrons – are thousand-times lighter and faster than nuclei. Understanding their behavior in atoms and molecules is crucial as well since they mediate light-matter interaction and are the main actors in chemical bonds. Electrons move on time scales of tens to hundreds of attoseconds (1 attosecond = 10-18 s) thus eluding femtosecond spectroscopic tools.
Only on the verge of the new millennium novel optical techniques came to the foreground, enabling the generation of attosecond bursts of extreme ultraviolet light. These tools enabled a novel spectroscopic discipline, Attosecond Science. Nowadays Attosecond Science discloses the intimate mechanisms of matter by elucidating how electrons behave on their own temporal scale inside atoms, molecules, and condensed matter.
Our group contributes to this exciting research in the following areas:
- Isolated attosecond light pulses
- High-order Harmonic Generation (HHG) in microfluid devices
- Optical Parametric Amplification (OPA) in the VIS and mid-IR
- X-ray Free Electron Lasers (XFELs)
- HHG with two-color fields
- HHG in solids
- HHG molecular orbital tomography
Ultrafast XUV/Soft X-ray spectroscopy
- Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy in molecules and solids
- Photoemission spectroscopy (PES) in molecules
- Ultrafast THz spectroscopy