Wave-vector and polarization dependence of conical refraction

We experimentally address the wave-vector and polarization
dependence of the internal conical refraction phenomenon by demonstrating
that an input light beam of elliptical transverse profile refracts into two
beams after passing along one of the optic axes of a biaxial crystal, i.e.
it exhibits double refraction instead of refracting conically. Such double
refraction is investigated by the independent rotation of a linear polarizer
and a cylindrical lens. Expressions to describe the position and the intensity
pattern of the refracted beams are presented and applied to predict the
intensity pattern for an axicon beam propagating along the optic axis of a
biaxial crystal.