Negative reflection, negative refraction and ray displacements in biaxial absorbing media, In4Se3

We show the existence of negative reflection and negative refraction in a slab of biaxial absorbing medium In 4Se3 placed between two isotropic media. We find the limiting angle of incidence in the slab for these phenomena to occur and its dependence with the orientation of the crystal axes. We analyze, both in reflection and refraction, the displacement of the ray with respect to the incident one at the output of the slab, finding a potential measure to experimentally study this effect.