Nonlocality in uniaxially polarizable media and cubic metamaterials

We highlight the impact of spatial dispersion effects on metamaterials electromagnetic properties. We revisit the problem of artificial magnetism in uniaxially polarizable media and prove that such structures can not be consistently described in terms of local permittivity and permeability tensors. Furthermore, we discuss the phenomenon of spatial-dispersion-induced birefringence in metamaterials with cubic symmetry and compare the measured magnitude of the effect with that known for natural crystals. Our results suggest that spatial dispersion in metamaterials turns out to be much more pronounced than in natural materials.