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."

Invisibility cloaking

[kngthdn]

It is not a 'magic cloak,' however.

Like this [ananova.com]?

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?

invisible??

[Awol411]

the whole basis of this is to stop the scattering of light that the object emits. so if there was no scattering, then wouldnt the object still appear black. sooo. couldnt you just look for the object that's all black. might work well in space or night time, but at 2pm on a sunny afternoon, i think i'll be able to spot the large black body trying to hide.

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.

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

[poopdeville]

This isn't as much of an issue as you might think. Imagine coating a stealth aircraft with very precisely made microscopic dust, and applying this technology to the particles. You'll end up with a macroscopic, radar invisible airplane.

Re:Invisibility cloaking

[kngthdn]

Here's an interesting article about it on the Scotsman [scotsman.com].

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.

"precise wavelength of most radar waves"

[mnemonic_]

You probably don't remember it because it doesn't exist. There are numerous radars using everything from millimeter waves (MMW) to multi meter long waves. Each type has its own specific uses, though I've heard that MMW radar is the most difficult technology to develop. But IANAEE (electrical engineer).

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.

Article Title Deceptive.

[Tavor]

It's not an "Invisibility Shield"... it's a useless optical illusion designed to fool everything.

*Say you somehow got this to work for a tank.*
>You chug along.
>Enemies hear you, but can not see you.
>Enemies open up, blind-firing.
>Though the Enemies have given away their positions, your tank is damaged to the point that it is no longer battleworthy.
*Congrats, Soldier. You just lost.*

Wow....

[groupthink]

So many different applications...

The concept could find uses in stealth technology and camouflage.

Stealth and camouflage!

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 [ananova.com] 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.

Re:been investigated a bit before

[MadcatX]

"Notably, plasma radar stealth has an opposite effect of the optical stealth. The aircraft would glow like a lightbulb, and leave a trail of glowing plasma in its wake. Also notably, aircraft at high hypersonic speeds induce a local plasma air environment, due to the tremendous energy of the aerodynamics."

Is it just me, or does this sound very familiar to what a UFO looks like, a large bright light? Even if optical stealth is compromised, if you applied this to spy drones, etc.., and with complete radar invisibility, then the public are going to think that they are UFO's and we all know how the military reacts when it gets calls about UFO's. It would make the perfect cover!

Although it wouldn't be the first time a spy drone was thought to a ufo by the general public:
http://www.wired.com/news/technology/0,1282,66588, 00.html [wired.com]

Re:Invisibility cloaking

[enigmals1]

No offense or trolling intended... but just to point out... how's your link any different than good old fashioned green/blue screen movie magic?

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

[biglig2]

Another aspect to it that they don't point out is that this does is make things invisible, not transparent. We all think of transparency when we think of invisibility, but if something is invisible - no light from it strikes our eyes - then we can deduce it's presence from the black blob moving about in the front room.

Which, since it only works on things too small to see, is not actually that big a deal I suppose...

P.S. you've inspired me to a new trend; I'm going to mark anyone who actually reads the article as a friend...

Radio Silence

[Doc Ruby]

"And of course the shielding would work fine for concealing large objects such as spaceships from sensors or telescopes that used long-wavelength radiation instead of visible light."

Now we know how advanced alien civilizations have remained "off the radar", despite our sweeping radar telescope surveys of their space abodes. They're not that much more advanced than us. But they've concentrated on the important bits: privacy technology. We'll neve catch up at this pace.