These are lenses that operate on a principle of "negative refractive
index". They are able to break the diffraction limit that was believed
to limit the resolution achievable in an optical system based on its
aperture and the wavelength observed:

Angular resolution.
http://en.wikipedia.org/wiki/Angular...on#Explanation

Already they are being used to create sub-diffraction limit images in
microscopy:

Metamaterials found to work for visible light.
Ames Laboratory researchers have found the first metamaterial known to
work for visible light, announcing the discovery in the Jan. 5 issue
of Science.
14:54, January 04, 2007
http://www.physorg.com/news87144852.html

'Superlens' has its reach extended.
Tom Simonite
17:23 01 February 2007
NewScientist.com news service
http://www.newscientisttech.com/arti...-extended.html

New superlens opens door to nanoscale optical imaging, high-density
optoelectronics.
22.04.2005
A group of scientists at the University of California, Berkeley, is
giving new relevance to the term "sharper image" by creating a
superlens that can overcome a limitation in physics that has
historically constrained the resolution of optical images.
http://www.innovations-report.de/htm...cht-43432.html

Sub-Diffraction-Limited Optical Imaging with a Silver Superlens.
Nicholas Fang, Hyesog Lee, Cheng Sun, Xiang Zhang*
Science, 22 April 2005: Vol. 308. no. 5721, pp. 534 - 537.
Recent theory has predicted a superlens that is capable of producing
sub-diffraction-limited images. This superlens would allow the
recovery of evanescent waves in an image via the excitation of surface
plasmons. Using silver as a natural optical superlens, we demonstrated
sub-diffraction-limited imaging with 60-nanometer half-pitch
resolution, or one-sixth of the illumination wavelength. By proper
design of the working wavelength and the thickness of silver that
allows access to a broad spectrum of subwavelength features, we also
showed that arbitrary nanostructures can be imaged with good fidelity.
The optical superlens promises exciting avenues to nanoscale optical
imaging and ultrasmall optoelectronic devices.
http://www.sciencemag.org/cgi/content/full/308/5721/534

However, the superlenses work by detecting near field light waves
which are quite close to the object being observed, within a light
wavelength.
A key question is can their use be extended to work for objects that
are far away, which would be required for astronomy.
There is some research on possible ways this might work:

Telescope resolution using negative refractive index materials.
Jack L. May and Tony Jennetti
Northrop Grumman Mission Systems (USA).
Proceedings of SPIE -- Volume 5166
UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts,
Howard A. MacEwen, Editor, January 2004, pp. 220-227
"Concepts are presented for using negative refractive index (NRI)
materials to design parabolic reflector telescopes and antennas with
resolutions significantly better than the diffractions limit. The main
question we are attempting to answer is can negative refractive
material be used to improve performance of parabolic systems even when
the signal or light source is far away and no evanescent fields are
present when they arrive at the parabolic reflector. The main approach
is to take advantage of any knowledge that we have to recreate the
evanescent fields. Fields are then adapted to improve a performance
measure such a sharper focus or antenna rejection of interference. A
negative refraction index lens is placed between the conventional
reflector and focal plane to shape the point spread function. To
produce telescope resolutions that are better than the diffraction
limit, evanescent fields created by the reflection off of the
parabolic surface are amplified and modified to generate fields that
sharpen the focus. A second approach use available knowledge of an
emitting aperture to synthesize a field at a distance that matches as
closely as possible the field of the emitting aperture. The yet
unproven conclusion is that techniques can be developed that will
improve antenna and telescopes resolution that is better than the
diffraction limit."
http://link.aip.org/link/?PSISDG/5166/220/1 [Abstract only]

If this succeeds then telescope apertures will only need to be a
fraction of their current size to achieve the same resolution. This
will be fundamentally important for space based telescopes.

The revolution in medicine and biology the superlens will allow has
to do with the confirmation of a hypothesized, but controversial, form
of life, the nanobacteria. I believe the nanobacteria will be proven
to exist and will be found to be pathogens for disease in humans.
There are for example some diseases that give the appearance of
infectious disease but for which no infectious agent has been
identified.
One such case is for example kidney stones. Some papers have been
written suggesting nanobacteria as their cause. Very small nanoscale
objects were seen in connection with the kidney stones but these
objects could not be confirmed as being alive.
The problem is these nanoscale objects can be seen for example with
electron microscopes, but this kills any putative life forms being
examined. The new superlens will allow these nanoscale objects to be
observed in optical wavelengths, at smaller sizes than the wavelengths
used, and as I say alive. You could for example do spectroscopy on
them to confirm they contain the organic molecules for life, and
perhaps as well observe their life cycle in real time.
The confirmation of a new form of life previously believed impossible
will certainly be revolutionary. The team that confirms them for
example I believe will be deserving of a Nobel prize. It's just a
matter of time, a short time.


Bob Clark