

"Invisibility cloak" can shield macroscopic objects in visible light - frisco
http://www.nature.com/news/2010/101215/full/news.2010.678.html

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defdac
"This cloak is able to conceal a macroscopic object with a maximum height of 2
mm, larger than 3500 free-space-wavelength, inside a transparent liquid
environment" The PDF is downloadable from here:
<http://arxiv4.library.cornell.edu/abs/1012.2783v1> The setup is only proven
with a laser from one direction with a specific green pattern. From page 8:
"The observer in all cases is assumed to have a fixed height of h"

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alanfalcon
"This cloak is able to conceal a macroscopic object with a maximum height of
2mm. [...] The observer in all cases is assumed to have a fixed height of h."

So we could hide microscopic hobbits from the Eye of Sauron?

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swombat
A video demo (with journalists present) would be nice... This is such science
fiction stuff that you really have to see it (or not) to believe it.

Kind of amazing that this is possible today. We really are living in the
future.

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michael_dorfman
You think? The whole thing seems paltry to me-- it is the equivalent of the
common magic trick of hiding objects via mirrors. You blanket a tiny object
with calcite, so that the light is bent around the object when viewed from a
fixed angle? Big whoop. Let me know when you can hide something the size of,
say, a shoebox, from an observer who can wander around freely, and I'll get
excited.

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redacted
I think you might misunderstand how these systems work.

Your mirror analogy is more correctly applied to current military stealth
systems: tricks of geometry are used to make the vehicle harder to detect.

With these "invisibility cloaks" there is _no_ indication to the observer that
the object _even exists_. The light appears to have passed completely through
the object and reflected off the surface below with no interference.

For further reading: <http://en.wikipedia.org/wiki/Metamaterial>

~~~
michael_dorfman
If I am reading the material correctly, the light appears to have passed
completely through the object _if and only if_ you happen to be sending the
beam of light of the wavelength they are expecting from exactly the position
they expecting.

In other words, big whoop.

~~~
aphyr
Did you even read the article? It explicitly states the cloak bandwidth
includes red, green, and blue optical frequencies. Calcite's dispersion
relation gives slightly different shifts for each frequency, but this is
nevertheless a huge step forward.

<http://arxiv4.library.cornell.edu/abs/1012.2238>
<http://arxiv4.library.cornell.edu/abs/1012.2783v1>

