The design rules of transformation optics generally lead to spatially
inhomogeneous and anisotropic impedance-matched magneto-dielectric material
distributions for, e.g., free-space invisibility cloaks. Recently, simplified
anisotropic non-magnetic free-space cloaks made of a locally uniaxial
dielectric material (calcite) have been realized experimentally. In a
two-dimensional setting and for in-plane polarized light propagating in this
plane, the cloaking performance can still be perfect for light rays. However,
for general views in three dimensions, various imperfections are expected. In
this paper, we study two different purely dielectric uniaxial cylindrical
free-space cloaks. For one, the optic axis is along the radial direction, for
the other one it is along the azimuthal direction. The azimuthal uniaxial cloak
has not been suggested previously to the best of our knowledge. We visualize
the cloaking performance of both by calculating photorealistic images rendered
by ray tracing. Following and complementing our previous ray-tracing work, we
use an equation of motion directly derived from Fermats principle. The rendered
images generally exhibit significant imperfections. This includes the obvious
fact that cloaking does not work at all for horizontal or for ordinary linear
polarization of light. Moreover, more subtle effects occur such as
viewing-angle-dependent aberrations. However, we still find amazingly good
cloaking performance for the purely dielectric azimuthal uniaxial cloak.Comment: 12 pages, 3 figures, journal pape