Ready to start: the reaction microscope is now coupled to the HHG-beamline
Initiated by the work of A. Zewail (Nobelprize in 1999), today´s
femtosecond laser systems are able to unveil nuclear dynamics in small
molecules in stunning detail. His idea of using ultra-short laser
pulses as a strobe for molecular systems both spurred a tremendously
rapid development on the field of femtosecond laser technology over the
last three decades and laid the foundations of femtochemistry.
At MPIK, the combination of femtosecond pump-probe techniques with
advanced detection techniques led to the direct observation of the
vibration in H2 and D2+ on a timescale of 11 femtoseconds (1fs = 10-15s).
However, the electronic motion in atoms or molecules, which typically
occurs within tens to hundreds of attoseconds (1as = 10-18s), remained unexplored, as the wavelength of Ti:Sa-based systems limits their pulse-length to about 4 fs.
This fundamental limitation in time resolution fell with the
investigation of high harmonic radiation (HHG), which turned out to
provide an efficient route to the production of coherent light pulses,
at least one order of magnitude shorter than conventional TiSa-systems
in the optical regime could ever provide.
Over the last five years, several experiments successfully demonstrated
that attosecond pulses created via HHG are able to trace electronic
response times via the so-called "attosecond streak mechanism".