Abstract
We developed a method for simulating the birefringence of an annealed ingot of MgF_2 single crystal caused by the residual stress after annealing process. The method comprises the heat conduction analysis that provides the temperature distribution in the ingot during annealing, the elastic thermal stress analysis using the assumption of the stress-free temperature that provides the residual stress after annealing, and the analysis of the birefringence of an annealed ingot induced by the residual stress. The finite element method was applied to the heat conduction analysis and the elastic thermal stress analysis. In these analyses, the temperature dependence of material properties and the crystal anisotropy were taken into account. In the birefringence analysis, we proved the equivalence of the Jones calculus and the average stress method. Then we calculated the optical path difference induced by residual stress, using the average stress method. In these analyses, we obtained the distributions of optical path difference with the symmetry of the crystal and the intrinsic birefringence caused by it.
