  Grating cloaks are a variation of dielectric carpet (or ground- plane)
cloaks. The latter were introduced by Li and Pendry. In contrast to the
numerical work involved in the quasi-conformal carpet cloak, the
refractive-index profile of a conformal grating cloak follows a closed and
exact analytical form. We have previously mentioned that finite-size conformal
grating cloaks may exhibit better cloaking than usual finite-size carpet
cloaks. In this letter, we directly visualize their performance using
photorealistic ray-tracing simulations. We employ a Newtonian approach that is
advantageous compared to conventional ray tracing based on Snell's law.
Furthermore, we quantify the achieved cloaking quality by computing the
cross-correlations of rendered images. The cross-correlations for the grating
cloak are much closer to 100% (i.e., ideal) than those for the Gaussian carpet
cloak.
