  We reconsider the refraction of evanescent waves at an interface between air
and negative index medium under the assumption that negative index medium is
necessarily dispersive and lossy. We show that all evanescent waves in air will
be refracted into decaying propagating waves inside a negative index medium,
with different spatial frequency components having different propagation
directions which are separated both in time and space; hence no refocus of
these evanescent waves is possible. Accordingly, all information encoded by
evanescent waves will be lost in the image making sub-diffraction-limited
imaging impossible.
