Salient Features of Temporal and Spatio-Temporal Metamaterials

In this communication we explore both analytically and numerically the exciting phenomena that can be obtained when the electromagnetic material parameters (permittivity and/or permeability) are rapidly changed in time. We will show how such a temporal change can be exploited to achieve phase conjugation of a monochromatic wave using a rapid periodic temporal variation of permittivity/permeability in a in a spatio-temporal slab/lens. Moreover, it will be also shown how a rapid variation of permittivity from a positive to a negative value in a physically (spatially) unbounded medium can lead to the enhancement of a stationary electromagnetic wave (i.e., a frozen field in the space without propagation).