Renewal of an fs amplifier system

• Subject Area: Condensed Matter Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 584522304

The aim of the project is to expand the experimental capabilities for time-resolved spectroscopic studies of condensed matter systems by extending access to the mid-infrared spectral range. This extension addresses scientific questions that require selective excitation and detection of specific electronic and vibrational degrees of freedom and that are only partially accessible with the currently available spectral coverage. Three scientific objectives are in focus. First, time-resolved investigations of transitions within bound excitonic states will be enabled in order to quantify coupling mechanisms and relaxation pathways in semiconductors and low-dimensional material systems at a microscopic level. Second, lattice vibrations and their coupling to electronic excitations will be selectively excited and monitored to gain insight into energy flow, dissipation, and possible nonequilibrium states in functional materials. Third, coupled electronic and ionic dynamics will be studied in complex material systems in which the interplay between ionic motion and charge carriers governs optical and electronic properties. The planned extension will complement and strengthen existing measurement capabilities in the near-visible and near-infrared spectral ranges. In particular, it will improve long-term stability and reproducibility for nonlinear experiments that require constant beam parameters and reliable conversion in downstream generation stages. This enables measurement campaigns over many hours to days under consistent conditions, which is essential for quantitative analysis and for meaningful comparison between samples and experiments. The implementation relies on targeted upgrading of performance-critical subsystems while continuing to use the existing laboratory and safety infrastructure, as well as established beam delivery and detection schemes. This approach ensures efficient realization of the scientific objectives without unnecessary replacement of fully functional components. Overall, the project will provide the basis for time-resolved experiments with extended spectral reach and improved stability, thereby enabling a deeper understanding of fundamental material and excitation processes on relevant time scales.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: fs-Verstärkersystem (Erneuerung)
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Justus-Liebig-Universität Gießen
• Leader: Professor Dr. Sangam Chatterjee