Optical and dielectric properties of partially resonant composites.

We analyze the two-dimensional potential around a coated cylinder placed in a nonuniform field. In two special cases the system behaves as if the core of the cylinder were enlarged and the shell absent. These are when the shell dielectric constant is the negative of either the core dielectric constant or the matrix dielectric constant. When the shell dielectric constant has a small imaginary part, the field can exhibit large fluctuations which remain localized near the surface of the coated cylinder.