  Electromagnetic field propagation through a transition layer between the
positive-index and negative-index materials with linearly changing dielectric
permittivity and magnetic permeability was investigated. It is shown that at
oblique incidence, the components of both TE- and TM-waves exhibit singular
behavior in the vicinity of the point where both dielectric permittivity and
magnetic permeability are equal to zero. In this case, finite dissipation of
electromagnetic field energy takes place even at infinitesimally small values
of losses. These results are applicable to a broader class of inhomogeneous
metamaterials and may provide a new platform for the realization of low
intensity nonlinear optics in metamaterials.
