Some time ago it was shown that a slab of material with, a relative
electrical permittivity \epsilon of -1, and a
relative magnetic permeability \mu of -1
and suspended in vacuo, has the ability to focus a perfect image: both the
near field and far field components are delivered to the image plane with
the correct amplitude and phase reproducing every detail in the original
source [1]. Real materials fall short of this ideal particularly in respect
of losses which manifest themselves as imaginary components to \epsilon and
\mu. In this talk we shall examine how to minimise the restrictions imposed
on the lens. For example, we have been able to show that a slab of negative
refractive index imbedded between two media of different (positive)
refractive index also behaves as a near-perfect lens whose performance is
limited by only the effects of absorption and retardation. that a slab of
negative refractive index imbedded between two media of different
(positive) refractive index also behaves as a near-perfect lens whose
performance is limited by only the effects of absorption and retardation.
It is only necessary that the perfect-lens conditions, which are also the
conditions for the existence of a surface mode, are met at one of the
interfaces.
References:
[1] "Negative Refraction Makes a Perfect Lens" JB Pendry Phys. Rev.
Lett. 85, 3966-9 (2000).