In article om,
Robert Clark wrote:
"The yet unproven conclusion is that techniques can be developed that will
improve antenna and telescopes resolution that is better than the
diffraction limit."
If this succeeds then telescope apertures will only need to be a
fraction of their current size to achieve the same resolution.

Careful here. "Better than" doesn't necessarily mean "much better than".
If memory serves, the far-field diffraction limit is a fairly direct
consequence of the Uncertainty Principle, which means that you may be able
to cheat on it a bit with a sharp lawyer :-), but it's *not* going to just
go away. Mumbling about "recreating" the evanescent fields ignores the
question of whether enough information is present to do so.

Also note carefully that some of the techniques they are discussing assume
that the shape or some other characteristic of the emitter is *known*.
It's easy to get "resolution" better than the diffraction limit if you
know what you're looking for; for example, a small object can be detected
against a contrasty background even if its size is well below the
diffraction limit. (The classic example is that under good conditions,
astronauts looking down from orbit can see things like roads, which are
demonstrably much narrower than the diffraction limit of their eyes.)

Even the claim that negative-refractive-index microscopy may revolutionize
biology has more hype than substance. There are *already* several methods
for doing *near-field* optical imaging to resolutions much better than the
diffraction limit, and they have proven useful but not revolutionary.
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