Nonlinear Dynamics in Semiconductor Lasers - Abstract
The quantum cascade laser (QCL) is an extremely versatile light source. By employing artificially engineered optical transitions in the conduction band of a semiconductor nanostructure, the mid-infrared and terahertz regimes can be covered, which are inaccessible to conventional semiconductor lasers based on electron-hole recombination. The possibility to also design the nonlinear optical properties of the QCL active region has been exploited for various innovative applications. This includes mode-locked QCLs for the generation of ultrashort optical pulses, as well as frequency comb sources providing an equidistant line spectrum, as used for innovative applications in metrology and spectroscopy. Moreover, frequency conversion structures enable the room temperature generation of THz radiation with broadband tunability. For the further development of these QCL sources, a reliable simulation model is needed, allowing for systematic design optimization and providing an improved understanding of the complex carrier-light dynamics. We show that for self-consistent simulations without empirical parameters, a multi-domain approach is required, describing the associated physical effects at various levels of complexity and employing a broad range of different numerical methods.