Optical Stealth Possible?

[Michel Van]

you know it from TV

in Star Trek, the Klingons and Romulan use Cloaking device
or in Anime Full Metall Panic, have Invisible Helicopter.

only Sci Fi ? NO !

in 2006 David Schurig and his colleagues at Duke University in Durham,
imagined the first and most primitive Cloaking device .
It consists of a ring of several layers of copper wire and fiber glass slides, and work only on microwave (radar)
on wavelength of 3.5 cm

in 2007 Christopher Davis and his colleagues have developed a camouflage cap, the visible light bend around them.
its oly green waveleng but it works!

Their camouflage cap consists of concentric rings. However, the material is another:
It consists of a transparent acrylic, on a thin gold layer is raised.
more on that work here
http://arxiv.org/ftp/arxiv/papers/0709/0709.2862.pdf

The path to a genuine camouflage cap is still far.
The previously presented camouflage caps work only in two dimensions

but Mathematicians Allan Greenleaf has idea for that
he called it "Electromagnetic Wormhole"
Greenleafs idea: Take a rectangular piece of camouflage material, roll it into a cylinder and then put in the inside of the cylinder of that thing, you want to disappear.

source (in german languade only)
http://www.spiegel.de/wissenschaft/mensch/0,1518,524320,00.html
http://www.spiegel.de/wissenschaft/mensch/0,1518,511566,00.html

Attach Picture
1: Cloaking device for Microwave
2: Electromagnetic Wormhole
3: The images show how the so-called meta-materials radiation to the ring.
So viewers get the impression that there was not the ring

 

[Justo Miranda]

- In 1943, an experiment was performed under the Yehudi code-name to diminish the frontal visibility against the luminous background of the sky. It consisted of 10 sealed-beam lights, installed along the wings leading edges and the rim of the engine cowling of an Avenger TBM-3D bomber. The tests proved that the Yehudi system lowered the visual acquisition range from twelve to two miles.

The entry into service of the new centimetric radars, that the ‘Metox’ detectors of the Kriegsmarine could not detect, disrupted the balance in the Battle of the Atlantic, rendering the Yehudi useless. But the experiments went on using a Liberator and were only declassified in the 80s.

During the Vietnam war, the idea was resumed under the ‘Compass-Ghost’ code name and the tests made with a blue and white F-4 Phantom, lighted by nine high-intensity lamps on the wings and fuselage, reduced the detection range a 30 percent.

In the mid 90s, the advanced achieved in Computer Generated Holography, wavelength computation with Fourier transform method and Point Source Holograms, allowed the creation of holographic images in 3D around an object to hide it. But the system just worked with static objects and the Phased Array Optics required a considerable amount of electronic equipment.

In 2003, researchers at the University of Tokyo developed an active camouflage system with video cameras that registered the background to project it against the object that should be camouflaged.

In 2004, the discovery of the graphene made possible the manufacturing of curve video screens and adapts them to any surface. An aircraft with a coat of grapheme screens and equipped with video cameras that register the background from any angle and project it on the screens at the other side, may become practically invisible.

The layers of grapheme are super-thin and several of them, with different properties, may be superimposed. Under the optical screen, it is possible to locate a layer formed by hexagonal elements of grapheme that may be heated or cooled down in a selective way, thanks to the ‘Adaptiv’ system, developed by BAE systems in 2011. This layer would very efficiently act as IR camouflage.