As part of the department of nano- and microcharacterization at IPS, the Femtosec group performs 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. A special emphasis is on the exploitation of the „low alpha mode“ at ANKA, which is capable to deliver 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.
The Femtolab clusters expertise on ultrafast optical methods and pulse lasers, which serve the Femtosec group, but also diagnostics of the electron pulses in the ring and the development of new accelerator concepts and techniques.
The research is funded by ANKA/ISS and by individual grants of the German Science foundation (DFG). AP is funded by the Heisenberg fellowship in 2009-2011. Collaborations are related to the Center for Applied Photonics (CAP ) Konstanz. We acknowledge the support and provision of beam time by IPS, SLS and ESRF .
The research of the group can be roughly sorted along the following subjects:
- Laser control of materials via lattice excitation
- Structural dynamics of nanoparticles
- Nanoparticle synthesis
- New Sources and methods with ultrahigh time resolution
The activities of the Femtolab consist in the provision of laser-based methods to process materials, in particular on the nanoscale. As a major part a femtosecond laser system is operated to be used for pump-probe experiments with radiation from ANKA as probe radiation.
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.
View of the ablation chamber with the optical port for the focussing 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.