"Time-resolved optical spectroscopy enables the study of the dynamical properties of charge carrier and spin states in solids on very short femtosecond time scales. This includes, for example, the quantum mechanical evolution of optically excited electron states, as well as their decoherence and relaxation processes. Of particular interest are the interactions between different fundamental quasiparticles in the solid state, such as excitons, magnons, plasmons, and phonons. To this end, we are investigating novel hybrid structures that combine different materials: Semiconductors with excellent optical properties, ferromagnetic materials with strong exchange interaction, and metallic nanostructures for localized confinement of electromagnetic fields. To experimentally investigate these phenomena, we use various high-precision optical measurement methods such as ultrafast excitation-interrogation experiments (pump-probe), or time-dependent four-wave mixing in combination with magnetic fields and polarization-dependent excitation and detection. In particular, we are working on the following topics and their further development:
- Photon echoes in semiconductor nanostructures.
- Spin interaction in hybrid ferromagnet-semiconductor nanostructures
- Plasmonic systems in combination with magnetic materials
- Excitation and control of spin waves in ferromagnetic structures by fs laser pulses".