  Metamaterials made of periodic collections of dielectric nanorods are
considered theoretically. When quantum resonators are embedded within the
nanorods, one obtains a quantum metamaterial, whose electromagnetic properties
depend upon the state of the quantum resonators. The theoretical model predicts
that when the resonators are pumped and reach the inversion regime, the quantum
metamaterial exhibits an all-optical switchable conduction band. The phenomenon
can be described by considering the pole stucture of the scattering matrix of
the metamaterial.
