Thermal lensing in optical systems for laser beam guiding and shaping is a highly up-to-date topic touching many fields of science and application. The development of thermally stable optical systems requires, from an engineering point of view, the improvement of current simulation models to enable a comprehensive modeling of thermal lensing in order to enable the optimization of optical systems in the early design stage.

For the first time, this dissertation enables a holistic modeling of thermal lensing due to arbitrary temperature profiles based on numerical methods for a mathematically and physically valid coupling of thermo-mechanical and optical simulation tools. Based on these developments, simulative and experimental analyses of thermal lensing are conducted and methodologies for the compensation of thermal lensing and the derivation of material data based on a sophisticated combination of measured and simulated values are derived.