Engineers Devise Invisibility Shield

GerritHoll points out an article in Nature according to which "researchers at the University of Pennsylvania 'say that a "plasmonic cover" could render objects "nearly invisible to an observer.' Earlier attempts at invisibility worked by colouring a screen to match its background, like a chameleon. The described technique is new, because it works by the concept of reducing light scattering. It is not a 'magic cloak,' however, because it will not work for the full range of visible light and needs to be adjusted precisely for the shape of the object. However, the concept could find an application in stealth technology."

Comments

Invisibility cloaking

[kngthdn]

It is not a 'magic cloak,' however.

Like this?

Well, that actually requires a special viewfinder, so it's not quite as cool, but it sure *looks* awesome. Better than the "spot the spaceship" pic, anyway.

How long til I can buy this stuff at Walmart?

Re:Invisibility cloaking

[kngthdn]

Here's an interesting article about it on the Scotsman.

It says, Similarly, researchers in Tokyo are developing a camouflage fabric that uses a comparable principle where the background is projected on to light-reflecting beads in the material. Such systems are, however, dependent on the viewer from which the object is being concealed being in the right position.

I see no mention of Photoshop, but it does say it could be used by surgeons and pilots. Sounds pretty cool to me.

Obvious Applications

[poopdeville]

I can think of a couple of obvious applications, especially if the technology can be adapted to scatter microwaves. Tanks and mechanized infantry are pretty obvious, but I think we want to avoid battleships unless we want a repeat of the Philadelpha Experiment and the crappy movie versions (though I loved the first one as a kid).

But what about non-military uses? Perhaps a "coat" of plasma on windows to reduce cooling bills in the summer? Or another coat of plasma on TV's to reduce glare? I can't think of anything particularly inspiring.

The shadow effect

[Dikeman]

The article puts two techniques next to eachother, as if it were alternatives for the same problem. This is false.
The proposed system with plasmonic covering reduces the scattering of light. The lightwaves pass by the object as were the object very small, smaller than it actually is. Hence it only works with objects that are allready very small, because otherwise the object would cast a shadow. (Light passes by, not through)
The system with light detectors and emitters mimics the scene that is behind (bigger) objects with respect to the viewer. You could actualy say that it fills in the shadow cast by the object.

So were the first system reduces the shadow effect, the second replaces the shadow alltogether. I could actualy see these two systems used along side eachother rather than instead of eachother.

front projection

[Metryq]

The Japanese "invisibility cloak" is nothing more than the front projection technique used in 2001: A SPACE ODYSSEY and many other films. That's like claiming that we have a super weapon that can hit an enemy anywhere -- provided he stands right here on this spot marked X. The alleged surgical and pilotting applications sound equally silly. It is an infinite regression of "if we can fit a camera in front of the surgeon's hands, we can project an image behind them to make a really cool effect that they are invisible!"

Re:Indeed, it's pretty far from advertised...

[bw_bur]

This wouldn't work. The radar would pass through the molecules, only to reflect off of the aircraft skin

Exactly. Hopefully someone will mod you up...

Now, if it could be set up so that the radar would pass through once, and bounce around between the skin and the coating before finding the right angle to escape, it would probably make the radar bounce off the plane at all kinds of weird angles (making the radar useless).

The problem I'm wondering about is: What happens if the radar can't find a way out? Will it keep bouncing around, loosing energy all the while, heating up both the skin and the coating (this may become an issue)?

These are the two conventional approaches to stealth: either deflect incoming waves anywhere but back towards the detector, or absorb as much as possible, in which case the coating inevitably heats up. I don't think this is much of an issue though: probably much more heat is generated simply by flying at high speeds.

Fighting back against misuse of words

[tod_miller]

This technology is really invisibility in the sense that it stops light scattering, but for visible light would only work for microscopic items...

Which must be working because right now I so not see many single microscopic items anyway...

It can't be used to conceal guns from Xrays, which use 0.1nm-20nm wavelegths.

Hiding missiles from radio based radar? Possible?

So shielding from visible light would be possible only for microscopic objects; larger ones could be hidden only to long-wavelength radiation such as microwaves. This means that the technology could not be used to hide people or vehicles from human vision.

Also the 'inventiveness' of the invisibility cloak is much less than its engineering feat.

We all have our own ideas about projecting the view behind your onto the front... from all angles... technically how to do it flexible, and stop illumination / shadow is very hard.

Not impossible, with some very clever technology that can 'feel' its own shape, and sense light conditions, can absorb almost all light (be dark even in bright light, if a shadow is behind you), and shine as bright as the sun on a rock (if you are in the shade, but a bright rock is behind you, and you cannot use the sun on the material to compensate)

This would require some l33t processing skills to handle the data.