The 4th Physics Institute concentrates on research in the field of ultrafast nanooptics. On the one hand the interaction of light with sub-micrometer sized structures is studied. On the other hand the basics and applications in the area of ultra-short and ultra-broadband laser pulse generation are investigated.
Concerning the nanostructures, our research is primarily focused on the light-matter interaction of systems with metallic nanoparticles, which possess so-called plasmonic resonances, originating in collective electron oscillations in the conduction band of the metals. We study the mutual coupling of such resonances in metallic nanoparticles as well as their interaction with the surrounding media, including chiral and non-reciprocal materials. Furthermore, we investigate the linear and nonlinear optical properties of quantum objects in the vicinity of metal particles, which are enhanced and modified by the high field intensities close to the metal-dielectric interfaces at resonance. Possible applications are new optical sensor devices, perfect absorbers, plasmon rulers, nanoantennas, as well as integrated photonic circuits.
Furthermore, our institute is doing research on femtosecond solid-state lasers, optical parametric oscillators and amplifiers. We have utilized tapered fibers as low-cost alternative for white-light supercontinuum generation and we are investigating novel optofluidic devices. With these laser sources we can cover the spectral range from the visible up to the mid infrared and the combination of these laser sources with functional nanostructured materials enables us to carry out unique spectroscopic experiments.
Our expertise spans from the fabrication of nanostructures and the construction of complex experimental setups to theoretical and numerical studies using commercial and in-house codes. Part of the institute are two junior research groups, namely Physical Optics and Ultrafast Solid State Spectroscopy.