The research covers several aspects of of nonlinear photonics and nonlinear quantum dynamics with fundamental and applicative aspects.

Self-organization in cold and ultracold atoms due to light-mediated interactions between atoms via feedback from a single mirror is explored to study complex phases and phase transitions including supersolids. A further activity is spontaneous magnetic ordering not only of dipolar but also quadrupolar degrees of freedom and potential connections to corresponding phases in condensed matter physics. These activities have strong interdisciplinary aspects being connected to self-organization phenomena in nonequilibrium system ubiquitous in Nonlinear and Complexity Science, technology and nature. The work is performed in close cooperation with the Computational Nonlinear Optics and Quantum Optics Group within the Optics Division.

In semiconductor lasers, we investigate their highly nonlinear dynamics, especially in vertical-cavity devices like VCSELs and VECSELs, with a focus on polarization dynamics and spintronics on the one hand and transverse mode structure and solitons on the other. This aims in particular on the understanding of the complex nonlinear processes determining (and partially limiting) the performance of semiconductor-based photonic devices and lasers, their control and the utilization of nonlinearities for applications. Recently, I became interested in thermodynamics aspects like photon condensation providing a further fruitful link between my research fields.