Refraction holodiagrams between two birefringent materials

Holodiagrams developed by Abramson and known as tools that permit the analysis of the geometrical aspects related to different optical phenomena are here extended to include the more general case when the elements that change the direction of light propagation are refractive and are composed by two birefringent uniaxial materials. The constructed holodiagrams consider the cases for the extraordinary rays for the most general orientations of both optical axes.The curves obtained, representing the loci of equal optical path between a source point in one medium and an observation point in the other, show a complicated shape that differs from that already known for isotropic materials. Some peculiar non-trivial facts are found in this way, such as surfaces of no deviation and generalized Fresnel zone plates to conjugate object points in one medium with image points in the other or in the same in the presence of arbitrarily shaped interfaces. The total reflection phenomenon in the interface between such materials is also considered.