Negative refraction in a uniaxial absorbent dielectric material

Refraction of light from an isotropic dielectric medium to an anisotropic dielectric material is a complicated phenomenon that can have several different characteristics not usually discussed in electromagnetics textbooks for undergraduate students. With a simple problem wherein the refracting material is uniaxial with its optic axis normal to the interface plane, the phenomena of (i) negative/positive refraction, (ii) negative/positive phase velocity, (iii) counterposition of the phase velocity and the time-averaged Poynting vector, and (iv) 'negative refraction' of the energy flux density can be examined. The last-named phenomenon is really negative deflection by refraction.