  Optical space in metamaterials may be engineered to mimic the landscape of a
multidimensional Universe which has regions of different topology and different
effective dimensionality. The "metamaterial landscape" may include regions in
which one or two spatial dimensions are compactified. Nonlinear optics of
metamaterials in these regions mimics either U(1) or SU(2) Kaluza-Klein
theories having one or more kinds of effective charges. As a result, novel
"photon blockade" nonlinear optical metamaterial devices may be realized.
Topology-changing phase transitions in such metamaterials lead to considerable
particle creation perceived as flashes of light, thus providing a toy model of
birth of an individual physical Universe.
