Attosecond Metrology and Spectroscopy

Time resolved investigations of electron dynamics in a variety of sample systems as atoms, molecules and solids establish the spearhead of modern ultrafast science. The technology that enables scientists to track and control these processes is referred to as “attosecond metrology” and is associated in symbiosis with ultrashort laser source development.
The origin of attosecond metrology is linked to the advent of ultrashort mode locked laser sources-femtosecond lasers, chirped pulse amplification, carrier-envelope-phase stabilization-and the technological aspects of this development that rendered experiments with a temporal resolution of tens of attoseconds possible. The high-order harmonicgeneration process yields laser pulses in the wavelength region around 10 nm with durations below 100 attoseconds, at the same time being the shortest controllable signals. We introduce the different spectroscopic techniques that make use of this unprecedented temporal resolution. While the “attosecond transient recorder” constitutes an oscilloscope for electromagnetic fields oscillating at visible frequencies,“attosecond tunneling spectroscopy” as well as “attosecond transient absorption” provides real-time insight into the dynamic processes of electronic rearrangements in matter.