Calculation of thermal-gradient-induced stress birefringence in slab lasers-I

A thorough analysis of the losses due to thermal-gradient-induced stresses in slab lasers is presented in which depolarization losses due to thermal-gradient-induced stresses are calculated properly by treating the changes in the dielectric impermeability tensor. In previous analyses of this problem, the approach in which the index of refraction is treated as a tensor quantity is only applicable in the limit of very small changes. Issues of how to correctly write the reduced-suffix forms of the tensors are also considered. Our formalism is then applied to an edge-pumped Yb:YAG slab laser. We consider straight-through propagation as an example of the formalism and indicate its application to the case of zigzag propagation.