Advanced numerical modelling is used to precisely calculate the extracted energy and limiting thermo-optical effects on cooled gain media used in high-power solid-state laser systems. The available geometries are rod, disk, and slab. A number of different laser components and devices can be modeled, including laser materials, nonlinear materials and optical materials for high-power laser systems. The team has a strong collaboration with the National Institute for Fusion Science (Japan) in the area of characterization of magneto-optical materials.