Our newly established group is currently setting up experiments to study the ultrafast evolution of
solids after resonant excitation of the lattice. The aim of these studies is to understand the role of
specific lattice modes in determining the microscopic and macroscopic properties of the solid, as well
as exploring the possibilities to control the material properties transiently via mode-selective lattice
The lattice excitation is realized with two complementary techniques: (i) direct mid-infrared and (ii)
impulsive Raman excitation. For mid-infrared excitation, we use the ps-pulses generated by the recently
commissioned FHI Free Electron Laser (FEL). Impulsive Raman excitation is achieved with
tunable femtosecond laser pulses in the visible to ultraviolet region from a table top fs laser system.
We use a wide range of optical and electrical probes to follow the response of the sample to the lattice excitation.
Making use of the special pulse structure of the FHI FEL, we develop new spectroscopic techniques to access
dynamics on mixed ps/ns timescales in the sample response by combining the ps pump-probe method with ns-resolved
real-time detection within the FEL macropulses