Laser Dynamics

The group contributes to the following application oriented research topics of WIAS:

Semiconductor lasers are compact, efficient and reliable light sources playing a crucial role in many modern technological systems. Depending on parameters and on their geometry, laser devices demonstrate a variety of complex dynamical regimes. A comprehensive study of the underlying nonlinear processes and bifurcation analysis leads to a better understanding of the observed behavior. This knowledge supports the design of new types of laser devices for specific purposes. [>> more]

Modern semiconductor and optoelectronic devices such as semiconductor lasers or organic field-effect transistors are based on semiconductor structures, which e.g. can be given by doping profiles, heterostructures or nanostructures. For the qualitative and quantitative understanding of the properties of these devices, mathematical modeling and simulation of the most relevant and, respectively, of the limiting carrier transport processes is necessary. In the context of the Green Photonics Initiative new topics move into the focus of research, e.g. reduced energy consumption of devices, new applications in the field of renewable energies, communication and lighting. [>> more]

This application deals with extreme nonlinear optics, and in particular with the propagation of intense ultrashort pulses in optical fibers. The propagation and stability of these pulses are studied by novel numerically effective models, which correctly account for both nonlocal response effects and basic physical constraints. For the latter, it is important to keep the causality principle, leading to the intrinsic Kramers-Kronig relation between dispersion and dissipation. In addition, the correct behavior of the medium response for large frequencies should be reproduced by the model. Furthermore, propagation equations are used to investigate long-living solitary solutions and mutual interactions of extreme few-cycle optical pulses. [>> more]

Mathematical modeling of electrons in semiconductor nanostructures and molecules requires a quantum mechanical description using the Schrödinger equation. In semiconductors, e.g., the electronic band structure, which determines the functionality of devices, can be understood by this means. The simulation of time-dependent processes such as the coherent evolution of electrons in semiconductor nanostructures or the evolution of chemical reactions is of major interest in numerous applications. Modeling dissipative processes requires evolution equations for density matrices that describe the interaction of qauntum particles with their macroscopic environment. [>> more]