Transmission of evanescent wave modes through a slab of DNG material

Abstract

We study the transmission of evanescent plane-wave components through a slab of double-negative (DNG) material (i.e., a medium with relative electromagnetic material parameters /spl epsiv/<0,/spl mu/<0). As is well-known by now, the monochromatic wave components that emerge on the far side have regained the energy apparently attenuated in the DNG slab (which would have been lost in tunneling of an evanescent wave component through an ordinary medium). However, there is a minimal slab width d of any DNG medium beyond which the field amplitude of any signal with nonzero bandwidth will decay with increasing d. The decay appears to be unavoidable in far-field imaging through a slab of the previously studied medium. This study extends the validity of this effect to an arbitrary DNG medium.