Division C: Nonlinear Processes in Condensed Matter

Director: Prof. Dr. T. Elsaesser, Humboldt University, Berlin

Division C was headed by Prof. Dr. Thomas Elsaesser until September 30, 2022. He holds a joint appointment in experimental physics with HU Berlin. The search for a successor of Prof. Elsaesser is ongoing. Ultrafast processes in condensed matter and their applications in technology represent the main research topics of Division C. Dynamics of equilibrium fluctuations and nonequilibrium excitations are studied in bulk and nanostructured solids, in particular semiconductors and ferroelectrics, molecular liquids, and hydrated biomolecules. This work aims at a basic physical understanding of processes and interactions at the atomic and molecular scale. It makes use of the most advanced methods of ultrafast spectroscopy, including femtosecond two-dimensional spectroscopy in the infrared and terahertz spectral range. Photoinduced structural dynamics of (poly)crystalline materials represent a complementary research topic which is addressed by femtosecond x-ray diffraction and absorption techniques. Novel lasers for ultrashort pulses, methods for measurements on ultrashort time scales, and the characterization of optoelectronic devices are subjects of applied research in Division C.

Division C consists of three departments:

In summary the areas of competence are described as follows:

Experimental

• Spectroscopy of solids and molecular liquids in the sub-50 fs regime
• Femtosecond nonlinear infrared and terahertz spectroscopy of solids and molecules including multidimensional techniques
• Femtosecond x-ray diffraction and absorption
• Generation of femtosecond pulses in diode-pumped solid state and fiber lasers and OPCPA systems, wavelength range 200 nm - 20 µm
• Generation of intense terahertz pulses and field-resolved characterization
• Generation of hard x-ray pulses in laser-driven laboratory sources
• Spectroscopic techniques for studies of aging and strain in laser diodes

Analysis and Simulation

• Nonlinear high-field transport in solids
• Time-resolved charge density maps in solids
• Nonlinear two-dimensional vibrational and terahertz spectra

In the framework of the research structure of the MBI, scientists of division C participate in the following projects:
 

Close Collaborations also exist between

3.1 and project 2.1 Time-resolved XUV-science

3.1 and project 3.2 Solids and Nanostructures: Electrons, Spins, and Phonons