The Femto Lab. covers research with time-resolved x-ray scattering and spectroscopy, in particular for the analysis of nanoscale dynamics, phonon excitation or phase transitions in the condensed phase. Special emphasis is on the exploitation of the „low alpha mode“ at KARA, which is capable of delivering pulses as short as 1 picosecond. In the x-ray regime this can be used for pump-probe experiments with femtosecond laser excitation, while in the THz region the coherent emission of the radiation can be sampled by means of electro-optical techniques.
Expertise includes ultrafast optical methods and pulsed lasers for research on laser-matter interactions, diagnostics of the electron pulses in the ring, and the development of new accelerator concepts and techniques. Research is funded by KIT and by individual grants of the German Science foundation (DFG). Collaborations are related to the Center for Applied Photonics Konstanz. Beamtime is provided by IPS,the SLS and the ESRF.
Current and previous research addresses the following topics:
The laser itself (500 MHz oscillator by Gigaoptics, pulse length 30 fs) is located on a mobile optical table, which also carries essential control electronics and can optionally be used under inert atmosphere (helium, nitrogen). Recently a nanosecond laser has been provided for high-power laser ablation on solid targets.
The image shows the ablation chamber with the optical port for the focusing of the laser on the front left side and a continuous rotation of the target disk inside the seald chamber (black stepper motor coupled to the magnetic transducer). Water flow is used to replace the liquid between individual laser shots.