Fluorescence losses from Yb: YAG slab lasers

We report on the distribution of fluorescence that can be emitted through the surfaces of a ytterbiumdoped yttrium aluminum garnet (Yb:YAG) slab-shaped high-power solid–state laser. Slab shapes considered include parallel or antiparallel Brewster endfaced slabs and rectangular parallelepiped slabs. We treat cases in which all the faces of these slabs are in air, or with water or another coating on the largest faces. The fraction of the fluorescence emitted through each face, its distribution over that face, and the directions in which it travels are shown to be important to the design of high–power slab lasers.