Slashdot Log In
Scientists Closer To Invisibility Cloak
Posted by
timothy
on Mon Aug 11, 2008 08:49 AM
from the excellent-for-parties dept.
from the excellent-for-parties dept.
Aviran was one of many readers to submit news of a just-announced development in the ongoing quest to develop a working invisibility cloak, writing: "Scientists say they are a step closer to developing materials that could render people and objects invisible. Researchers have demonstrated for the first time they were able to cloak three-dimensional objects using artificially engineered materials that redirect light around the objects. Previously, they only have been able to cloak very thin two-dimensional objects" Reader bensafrickingenius adds a link to coverage at the Times Online, and notes that "the world's two leading scientific journals, Science and Nature, are expected to report the results this week." Tjeerd adds a link to a Reuters' story carried by Scientific American.
Related Stories
[+]
Science: Tsunami Invisibility Cloak 172 comments
BuzzSkyline writes "New Scientist is reporting on a lab-scale experiment that may lead to a tsunami invisibility cloak, which could protect islands, open-ocean platforms and even coastlines from dangerous waves by effectively making them invisible to tsunamis. The technology is based on the same sorts of negative index of refraction ideas that some physicists are exploring as they try to make an optical invisibility cloak, except that it works with water instead of light."
[+]
Science: A Step Toward an Invisibility Cloak 197 comments
Technology Review has a writeup on the latest advance in the lab towards an invisibility cloak made of metamaterials, described this week in Science. We've been following this technology since the beginning. The breakthrough is software that lets researchers design materials that are both low-loss and wideband. "The cloak that the researchers built works with wavelengths of light ranging from about 1 to 18 gigahertz — a swath as broad as the visible spectrum. No one has yet made a cloaking device that works in the visible spectrum, and those metamaterials that have been fabricated tend to work only with narrow bands of light. But a cloak that made an object invisible to light of only one color would not be of much use. Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, it's no longer effective. The cloak that Smith built is very low loss, successfully rerouting almost all the light that hits it."
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
I would have claimed 1st (Score:5, Funny)
I would have claimed 1st, but someone appears to be cloaked.
Re:I would have claimed 1st (Score:5, Funny)
His name was Robert Paulson. [imdb.com]
There fixed that for you.
Parent
Re:I do claim 1st (Score:5, Funny)
Don't know about the patent, but I can claim prior art. I have an invisible cloak that I wear all the time at home. I used to wear it in public, but kept getting arrested.
Is there an emperor out there looking for an outfit for a parade? I have a spare that I'm willing to sell.
Parent
Currently under "Cliche Movie Plot" (CPM) testing (Score:5, Funny)
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:4, Interesting)
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:5, Insightful)
I know everyone is making with the jokes,but I for one really don't like the idea of this. Yet again,we have scientists seeing if they CAN do something,rather than if they SHOULD do something. As aggressive as the US has been lately,does anyone really want gunships,fighter jets,and whole squads of special forces rendered invisible?
Hear hear! Perhaps we should revise the Geneva convention. From now on, all snipers must jump up and down waving their arms and yelling "Look at me" before taking their shot. All submarines must have PA systems that continually blast Rick Astley music when they're submerged. All spy drones must broadcast Flight of the Valkyries when on a mission.
I understand your point but, as long as the world has weapons, governments will be spending money on improving them (range/cloaking/accuracy/flexibility/etc.) If you go to the government leaders who control weapons funding and ask them "Should this weapon be improved?", once they're done laughing the answer will certainly be "Yes." And, assuming that this product would be fielded for military use as you imply, it would be seen as a measure to both increase our effectiveness on the battlefield and protect our troops. That would change the government's answer from "Yes" to "Hell yes." Right? Wrong? Doesn't matter - just the world we live in.
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:5, Insightful)
While we are limiting ourselves from creating an invisibility cloak do we have to ban warfare at night and stealth aircraft? I mean, those things just aren't fair. In fact let's get rid of guns, camouflage, body armor, aircraft, and submarines. We can settle things with a boxing match. Technological advances in warfare has continued for centuries now. We've been down this path before with other technology but I wouldn't be too worried. Just as devices like these are created others are created to defeat them. It is the natural progression of weapons.
Parent
Re: (Score:3, Insightful)
>Just as devices like these are created others are created to defeat them. It is the natural progression of weapons.
You mean tools, not weapons. Many things that have potential use as weapons have non-weapon uses as well. It's only a weapon when it's used as one. Otherwise it's a tool. A knife is a tool when you use it to slice bread.
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:5, Funny)
That's easy. Point your AK-47 at someone else and say "Slice that loaf of bread."
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:5, Insightful)
Even a perfect optical cloak would still be detectable in many ways. Bear in mind that wearing a perfect optical cloak will render you blind. This means you'll have to navigate using other methods. You could wear infrared goggles, but that means you're visible in infrared light and therefore detectable. You could make yourself invisible to all wavelengths, perhaps, and then navigate by sonar. A microphone will pick that up easily enough. Likewise radar. You could, I suppose, navigate via a remote camera signal that displays your surroundings on a screen located inside the cloaking device. That would be disorienting but one could probably train for it or use a VR representation of your surroundings. Assuming, then, that you can obfuscate the video signal and avoid emitting any light yourself, then you'll be foiled by a cheap fog curtain [rogergeorge.com] at the entrance of a building. Or, if you want to be more practical about it, a metal detector. If the target of your assassination attempt is outdoors, you'd best hope that there's no precipitation, smoke, smog, or fog. And you won't be able just to point and shoot, either. Remember, you're blind.
Even assuming a partial optical cloak that lets you be invisible "enough" (perhaps in shadows) and still see somehow, you'll still be detectable. If this technology becomes available, technology to defeat it will, too. Off the top of my head... a sonar or radar (preferably sonar, I think humans are transparent to radar) system that compares the visual or infrared spectrum with the echos. You probably wouldn't even need a human to operate it; a computer could simply find the discrepancies between the images and report them. A detection system like this would probably be affordable even to smaller nations. If you wanted to get really paranoid, you could even have the computer automatically target human-shaped echo discrepancies and fire long range or remote tasers at them, killing the cloak as soon as it is spotted.
Or, save yourselves all the trouble, sprinkle sand everywhere and just watch for footprints. Or hold all public events in the middle of huge, 2-inch deep lakes.
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:4, Insightful)
I don't think so. One may absorb some light without having to reflect any.
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:5, Insightful)
Then you'd be a dark spot, or two dark eye shaped spots.
Parent
Re:Currently under "Cliche Movie Plot" (CPM) testi (Score:4, Insightful)
Resistance to an idea won't prevent its reality.
This technology will ultimately be available, and mankind will never learn to cope with it until it is a reality.
If we hadn't pushed so hard for nuclear weapons (which have killed far far fewer people than, say, firebombs or religion), we wouldn't have had the cleanest safest source of energy on the planet as soon as we did. (Note: windmills are a joke, and solar panels don't last nearly long enough for their initial cost.)
If only there were a way to make some dastardly weapon out of geothermal power...
Parent
correction: (Score:5, Insightful)
Re:correction: (Score:5, Funny)
The fact that this is modded insightful is frightening in itself.
Parent
Re:correction: (Score:4, Funny)
Better than "+1 Hot".
Parent
arms race (Score:5, Funny)
And the locker room will be full of girls wearing invisibility cloaks.
Parent
Pictures? (Score:5, Funny)
At first I was going to complain about the lack of pictures, but then I realized they wouldn't be too revealing anyway.
Re:Pictures? (Score:5, Funny)
Parent
Re:Pictures? (Score:5, Funny)
Has it occured to anyone that once you take the cloak off you had better not set it down?
It really adds a whole new level to losing your keys if you set the cloak on them by mistake.
On a brighter note voyeurism just got easier..
Parent
Re:Pictures? (Score:5, Funny)
Mr. Nesbitt has learnt the first lesson of not being seen... not to stand up. However, he has chosen a very obvious piece of cover.
Parent
Re:Pictures? (Score:4, Funny)
Don't forget the film demonstration:
This is Mr Lambert of Lewton. He cannot be seen. Mr Lambert, will you remove your invisibility cloak please? (gunshot and scream)
This demonstrates the value of not being seen.
Parent
Science writing at its finest (Score:5, Funny)
Very thin 2D objects eh? Nice.
Re:Science writing at its finest (Score:5, Funny)
It has trouble with very thick 2D objects.
Parent
Re: (Score:3, Insightful)
What about very short but thick 2D objects?
And then... (Score:4, Informative)
War Application (Score:4, Interesting)
Re:War Application (Score:5, Informative)
Parent
Re: (Score:3, Funny)
I really hope that our wars aren't fought like Crysis in the future. The self-destruct feature probably makes sense for military use (and the idea of jumping fifty feet is pretty awesome), but I'd rather not deal with the frozen aliens.
Re:War Application (Score:5, Interesting)
Parent
Nature's Abstract (Score:5, Informative)
"the world's two leading scientific journals, Science and Nature, are expected to report the results this week."
You can find the Nature abstract here [nature.com]. And if you have a subscription, you can read the full research and see the data they collected from experiments.
According to the Ars Technica article on this [arstechnica.com], the Science link will be here [doi.org].
There seems to be a few more papers and articles on this but if you're interested you can search for optical metamaterials with negative refractive indexes.
enage cloaking device (Score:5, Interesting)
Re:enage cloaking device (Score:5, Interesting)
Parent
Re:enage cloaking device (Score:5, Insightful)
Parent
Re:enage cloaking device (Score:4, Informative)
I had to look up Snell's law quick, which doesn't mention wavelength as being a factor (I thought that the refective effects might vary according to wavelength), but then i noticed this at the bottom:
http://en.wikipedia.org/wiki/Snell's_law [wikipedia.org]
http://en.wikipedia.org/wiki/Dispersion_(optics) [wikipedia.org]
I would guess that any optical camoflauge technique has a function of input wavelength vs. camoflauge effectiveness, and that wavelenghths sufficiently on either side of "visible" would likely fall off of the effectiveness plateau.
Parent
Re: (Score:3, Interesting)
First we need to rembeer that light, infra-red, ultra violet and radar (among others) are just different wavelengths of electromagnetic waves. So the prisiple is the same but one "cloack" technology may be effective for some wavelengts but not others.
I'm just going to call it all emw for now.
To be invisible one need to take care of four things.
1. Not reflecting any emw from any emw-source to the sensor/observer.
2. Not to emit any emw to the sensor/
Old "news". Nothing to see here.... (Score:5, Insightful)
This was posted in Pharyngula yesterday. The usual prescient commenters noted that nowhere on the researchers' pages was there active speculation about an "invisibility cloak", and it was probably just some reporters going wacky over the possibilities. http://scienceblogs.com/pharyngula/2008/08/get_your_invisibility_cloak_he.php [scienceblogs.com]
Re:Old "news". Nothing to see here.... (Score:4, Informative)
"We are not actually cloaking anything," Valentine said in a telephone interview. "I don't think we have to worry about invisible people walking around any time soon. To be honest, we are just at the beginning of doing anything like that."
So, while they aren't saying 'this will become an invisibility cloak', to say that there is no active speculation about applying visible light metamaterials as a cloak is wrong. Article also ends with comment on how these would make superior lens for microscopes.
Parent
Look over there, a cloaked eye-catching headline (Score:5, Informative)
This story has popped up here and there in the press today, but when I actually RTFA the actual breakthrough is negative refractive index materials, in the visible spectrum.
The application is not invisible tanks and infantry, but microscopy.
See here for photoshopped image that enhances the misleading headline http://news.bbc.co.uk/1/hi/sci/tech/7553061.stm [bbc.co.uk]
Woot! (Score:5, Funny)
I dunno about this claim. (Score:5, Funny)
I can see the use for one of these (Score:4, Insightful)
To get my laptop past US customs without having it 'confiscated'...
Seriously though - how long do you think until any tech like this is restricted to military use only ? If you actually do achieve human-level visible-spectrum invisibility (even if you have to move very slowly to avoid being caught by reflection shifts and such and have to avoid anybody with IR) - it will be banned for civilian use like a shot. The people who want it for 'hunting purposes' will kick up a fuss but we couldn't take the risk of an invisible man sneaking into the white house and farting on the president's desk now could we ?
Okay... I tried to become serious but I failed... let's try this again:
Considering the real security implications of true invisibility from the naked eye - do you think it will be banned/restricted ? Do you think it SHOULD be banned or restricted ?
Invisibility cloak (Score:5, Funny)
I'll believe it when I see it.
Actually it was invented several months ago... (Score:5, Funny)
now they just can't find the blasted thing.
I just sold one of these (Score:3, Funny)
I have another one, but I put it down somewhere and now I can't find it.
Re:MIT (Score:4, Funny)
Parent
Re:First - talk about "Dup, dup, dup, Dup of Earl. (Score:3, Informative)
Re: (Score:3, Insightful)
A true invisibility cloak must gather every incident photon and then re-emit it out the other side of the cloak as if it had passed through the wearer.
The whole point of the negative index of refraction is the ability to do just that. We're obviously a long way from doing it, but scientists are beginning to see a glimmer of hope.
Re:Invisible? Not quite, I think (Score:4, Insightful)
No, the light gets bent around it perfectly. The light coming in from the background enters the metamaterial, is bent around to the other side of the object and exits it just as if it had passed through the area enclosed by the metamaterial without any obstacles. Ideally, there is no way that an observer could tell the difference with the exception of knowing the time of travel. The path through the metamaterial is longer than that of the perceived path. I would think that if the shrouded object was in front of a large reflector of a known distance from a radar like source, then the added delay in the signal would add a very small amount of distance to the location of the reflector. An astute observer with very good equipment may notice a change in the position of the radar returns as a cloaked object crosses through. There are further exceptions that are introduced the more you start to use the theory in practice, the biggest problem being that the current solutions would require that an object be encased in a spherical shell of metamaterial, not the most convenient situation. In addition, the current crop of metamaterials have very small bandwidths, making the cloaked object perceptible to other detection methods. If you cloaked for the visible (and actually could cover the entire visible region) then you would probably be easily picked up via radar or infrared imaging.
Parent
Re: (Score:3, Funny)
When are the flying broomsticks coming?
I see you've not met my ex-wife.