  We considered the experimental realization of a Tamm medium that is optically
equivalent to the collision of two linearly polarized gravitational plane waves
as a piecewise homogeneous metamaterial. Our formulation was based on the
homogenization of remarkably simple arrangements of oriented ellipsoidal
nanoparticles of isotropic dielectric-magnetic mediums. The inverse Bruggeman
homogenization was used to estimate the constitutive parameters, volume
fractions, and shape parameters for the component mediums. The presented
formulation is appropriate for the regions of spacetime where the two
gravitational plane waves interact, excluding the immediate vicinity of the
nonsingular Killing-Cauchy horizon at the focusing point of the two plane
waves.
