# Metamaterials: a real invisibility cloak



## a_majoor (18 Sep 2006)

Canada is becoming a leader in the investigation of "Metamaterials". Rather than go into the physics (which is rather freaky) the effect of metamaterials is to bend light, radio and radar waves in unexpected directions. By careful control of the material, you could literally bend light  or radar around an object, rendering it effectively transparent. Rather bizzare effects could be engineered into antennas and lenses using these materials, perhaps reducing the size of the lens compared to an equally powerful conventional optical device, creating powerful surveillance systems which could be incorporated into hand held devices.

Metamaterials working in the microwave frequency range are now being studied, and in 2005, a simple prototype that works with visible light frequencies was demonstrated.

There is an introduction in the October edition of Popular Science, and http://www.nserc.ca/news/2004/p040311_bio3.htm.


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## warspite (21 Oct 2006)

Not sure where to post this. Please move if it's in the wrong place.
http://www.cbc.ca/technology/story/2006/10/19/invisibility-cloak.html#skip300x250


> Scientists create 'invisibility' cloak that bends microwaves
> Last Updated: Thursday, October 19, 2006 | 12:09 PM ET
> CBC News
> A team of British and U.S. scientists has demonstrated the first working "invisibility cloak," although don’t expect it to appear in the Halloween costumes aisle just yet.
> ...



Could this have serious military application? Even if it could only hide a target from radar etc, it would seem to me to have enormous potential. Comments?


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## Sig_Des (21 Oct 2006)

Could you imagine?

This would be an amazing resource for ECW. Imagine hiding your CPs or RRBs from Directional Finding?


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## McG (21 Oct 2006)

warspite said:
			
		

> Could this have serious military application? Even if it could only hide a target from radar etc, it would seem to me to have enormous potential. Comments?


Eventually, yes.  Probably not for a while.


			
				Sig_Des said:
			
		

> Could you imagine?
> 
> This would be an amazing resource for ECW. Imagine hiding your CPs or RRBs from Directional Finding?


I don't think this will hide a transmitter from direction finding.  It would hide things from the ambient EM spectrum (including from detection systems that look for a return of their own EM broadcasts).


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## Trinity (21 Oct 2006)

How much energy would this thing need.   : : ???

Definitely NOT feasible for the next 20-30 years?


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## Klc (22 Oct 2006)

As the article said. You can hide a small copper rod from microwaves. If you can find a use for that...  :


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## McG (22 Oct 2006)

Today it's a rod.  In 25 years it could be a tank, destroyer or attack fighter that is hidden.


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## warspite (22 Oct 2006)

From theory to hiding this small copper rod, took five months. From here it would just be a matter of increasing the scale and efficiency. The main problem, as Trinity has said, will be how much power this thing will use to operate.


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## Bert (22 Oct 2006)

The trick to the technology is HOW it redirects microwaves, if "redirects" is the word to
accurately describe what the device does.  The article specifies microwaves but other
electromagnetic spectrums are not listed.

"Visibility" of radar usually within microwave bands rely on signal reflection or discernable
changes across a transmission field.  The technology would reduce the reflection by the
redirection of radar pulses and minimize discernable changes in RF fields.  Speculative
applications may involve radar/RF object detection countermeasures or in the reduction
of damaging solar/high power RFI fields.


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## McG (22 Oct 2006)

Bert ,
You are describing stealth technology when you talk of redirecting the radar pulses.  That is not what is described above (in which the radar pulses would still be seen undisturbed on the far side of the object).  When this technology is made to work (at it may be a very many years) then you would no longer be able to detect stealth aircraft through passive stations looking for scattered EM waves.


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## Bert (22 Oct 2006)

Sorry McG, I'm taking this right from the article:

>
Little more than 12 centimetres across, the small device can redirect microwave beams so they flow around a "hidden" object inside with little distortion, making it appear almost as if nothing were there at all.
<

The article doesn't provide a full scientific concept or technical specifications of the wave redirection.  It does specify 
"microwaves" which are a small part of the electromagnetic spectrum and redirect with "little" distortion.  The radar does 
detect reflections so the device may minimize or eliminate discernable radar signatures.  I was speculating the device could also mask 
objects passing through X-ray machines or lower/redirect solar RFI that affects satellites in time to come.


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## McG (22 Oct 2006)

The goal of the technology is no reflection/scattering.  You noted yourself (your first post above) that "redirects" does not fit the technology description.  I agree that the device could mask objects passing through X-ray machines, and this is probably much nearer in the future that any battlefield application.



> Crude invisibility cloak unveiled
> *Device makes microwaves slip around object*
> Oct. 19, 2006. 11:04 AM
> RANDOLPHE E. SCHMID
> ...


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## andreit1 (3 Nov 2006)

I would give it a maximum of 10 years before it is applied
to actual combat. Although by then a counter measure will surely have emerged. I say we go 
back to fighting with our fists.


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## I_am_John_Galt (10 Mar 2007)

Outta' control   ... just came across a video of this technology (wait for the end to check out the jacket): http://www.youtube.com/watch?v=VVi7mZ6XX3w


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## warspite (10 Mar 2007)

http://projects.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/oc.html
It's actually quite ingenious. As far as I can tell the reflective material only reflects the image you project, hence with an image of the background it masks the object behind it. Not an expert but should have potential for base security or security for any fixed location in general.


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## geo (11 Aug 2008)

http://news.bbc.co.uk/2/hi/science/nature/7553061.stm

Scientists in the US say they are a step closer to developing materials that could render people invisible. 

Researchers at the University of California in Berkeley have developed a material that can bend light around 3D objects making them "disappear". 
The materials do not occur naturally but have been created on a nano scale, measured in billionths of a metre. 
The team says the principles could one day be scaled up to make invisibility cloaks large enough to hide people. 

Stealth operations 

The findings, by scientists led by Xiang Zhang, were published in the journals Nature and Science. 
The light-bending effect relies on reversing refraction, the effect that makes a straw placed in water appear bent. 
Previous efforts have shown this negative refraction effect using microwaves—a wavelength far longer than humans can see. 
The new materials instead work at wavelengths around those used in the telecommunications industry—much nearer to the visible part of the spectrum. 
Two different teams led by Zhang made objects made of so-called metamaterials—artificial structures with features smaller than the wavelength of light that give the materials their unusual properties. 

One approach used nanometre-scale stacks of silver and magnesium fluoride in a "fishnet" structure, while another made use of nanowires made of silver. 
Light is neither absorbed nor reflected by the objects, passing "like water flowing around a rock," according to the researchers. As a result, only the light from behind the objects can be seen. 

Cloak and shadow 

"This is a huge step forward, a tremendous achievement," says Professor Ortwin Hess of the Advanced Technology Institute at the University of Surrey. 
"It's a careful choice of the right materials and the right structuring to get this effect for the first time at these wavelengths." 
There could be more immediate applications for the devices in telecommunications, Prof Hess says. 
What's more, they could be used to make better microscopes, allowing images of far smaller objects than conventional microscopes can see. 

And a genuine cloaking effect isn't far around the corner. 

"In order to have the 'Harry Potter' effect, you just need to find the right materials for the visible wavelengths," says Prof Hess, "and it's absolutely thrilling to see we're on the right track."


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## armyca08 (11 Aug 2008)

I read and wrote on an article on usenet a number of years back. It was essentially just a matter of having a light absorbant material that could also reflect those colours around it - cloaking. Or in the case of invisibility take the signal then transmit the signal from one side, map the digital characteristics of the space from point A to point b and display it. I have no doubts this technology existed over 5 years ago. in a 1 meter x 1 meter sized drone.


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## a_majoor (11 Aug 2008)

Metamaterials do not absorb wavelengths of light (or sound, there are some threads on metamaterials in the navy board and elsewhere in Army.ca), but rather refract them in a controlled manner. Think of how light is refracted in a glass of water when you dunk a spoon in it; the spoon looks broken where the light is refracted.

Metamaterials control the refraction in the manner the designer plans, metamaterials already exist for radio and microwave frequencies (imagine bending a radar beam around an aircraft or ship), and have been demonstrated for light and sound as well. invisibility in all wavelengths will be difficult to achieve, since refraction is a property of the wavelength of the light, radio or sound wave you are trying to bend, but even limited invisibility would be pretty freaky.


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## GAP (11 Aug 2008)

Especially in various forms of covert ops, etc.....


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## a_majoor (12 Aug 2008)

More on Metamaterials:

http://www.technologyreview.com/Nanotech/21213/?nlid=1268&a=f



> *Bringing Invisibility Cloaks Closer*
> The fabrication of two new materials for manipulating light is a key step toward realizing cloaking.
> By Katherine Bourzac
> 
> ...


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## tomahawk6 (12 Aug 2008)

Cant have a cloak without an energy shield. 
All we need for our space ship is a warp drive. ;D


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## Ecco (12 Aug 2008)

tomahawk6 said:
			
		

> All we need for our space ship is a warp drive. ;D



Here is your warp drive.
http://dsc.discovery.com/news/2008/07/28/warp-speed-engine.html


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## a_majoor (16 Jan 2009)

A broadband invisibility cloak is now within reach. Given that lightwaves are much smaller than sound or radio waves, it will be easier in theory to "cloak" aircraft and AFV's from radar, and submarines from sonar than to make objects disappear in the visible spectrum. My main question now is how well does this stuff work in controlling leakage of energy from the shielded object? (Damn, what is that thermal hotspot in the middle of the open field?)

Exciting stuff

http://www.technologyreview.com/computing/21971/?nlid=1694&a=f



> Friday, January 16, 2009
> *Invisibility-Cloak Breakthrough*
> New software has enabled metamaterials to work with a broad band of frequencies.
> By Katherine Bourzac
> ...


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## a_majoor (2 Apr 2009)

Notice this is a flat plate of material. This form factor is much easier to work with when building an actual object:

http://www.technologyreview.com/blog/arxiv/23270/?nlid=1908



> *Acoustic superlens could cloak objects from sonar*
> 
> First experimental demonstration of a technology that could trigger a new game of cat and mouse beneath the waves
> Wednesday, April 01, 2009
> ...


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## Recon 3690 (3 Apr 2009)

This brings to mind the 2 Philadelphia Experiment movies


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## a_majoor (17 Aug 2009)

Now other types of all aspect invisibility cloaks are being developed. Imagine being able to bring a smart weapon very close to the target before disclosing yourself by firing (or cruising far away and letting the weapon do an unpowered separation inside its own cloak before going active and hunting the target down?)

One aspect which is even more interesting is using this sort of technology "bend" earthquake and tsunami waves around an object. Can you bend shockwaves around a target and protect a military target from a near miss?

http://nextbigfuture.com/2009/08/numerically-shown-multiple-frequency.html



> *Numerically Shown Multiple Frequency Active Cloaking of Any Shape Object by Devices that Generate EM*
> 
> These images are from animated computer simulations of a new method -- developed by University of Utah mathematicians -- for cloaking objects from waves of all sorts. While the new method is unlikely to lead to invisibility cloaking like that in 'Star Trek' or 'Harry Potter' movies, it may eventually help shield submarines from sonar, planes from radar, buildings from earthquake waves, and oil rigs and coastal structures from tsunamis. The top three images show a wave front passing the kite-shaped object in the middle and hitting the object as it does. In the bottom three images, the kite-shaped object if surrounded by three cloaking devices and the waves they emit. So when the wave front passes, it moves by the object without touching it. Photo Credit: Fernando Guevara Vasquez
> 
> ...


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## Jarnhamar (26 Aug 2009)

NDHQ would be the biggest buyer.


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## a_majoor (19 Mar 2010)

Advancing the art:

http://nextbigfuture.com/2010/03/three-dimensional-invisibility-cloak-at.html



> *Three-Dimensional Invisibility Cloak at Optical Wavelengths*
> 
> A three-dimensional invisibility-cloaking structure operating at optical wavelengths based on transformation optics has been designed and realized. Our blueprint uses a woodpile photonic crystal with tailored polymer filling fraction to hide a bump in a gold reflector. Structures and controls are fabricated by direct laser writing and characterized by simultaneous high-numerical-aperture far-field optical microscopy and spectroscopy. Cloaking operation with large bandwidth of unpolarized light from 1.4- to 2.7-µm wavelength is demonstrated for viewing angles up to 60 degrees
> 
> ...


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## a_majoor (8 Apr 2010)

And now using metamaterials on the offense:

http://nextbigfuture.com/2010/04/sound-bullets-generated-by.html



> *Sound Bullets Generated by Metamaterials for Killing Cancer Tumors or Submarines*
> 
> PNAS - Generation and control of sound bullets with a nonlinear acoustic lens
> 
> ...


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## GAP (20 Jan 2011)

Invisible Tanks, Planes and Armor Could Hit Battlefields in 5 Years
Article Link
Published January 18, 2011

Invisible tanks -- and maybe invisible soldiers -- may soon be charging onto battlefields.

A British weapons manufacturer is making good on the promise of Wonder Woman's invisible jet, describing an "eCamouflage" system that uses electronic ink to disguise combat vehicles by projecting videos of the countryside onto them -- electronic squid ink of a sort.

Using highly sophisticated electronic sensors attached to a vehicle's hull, BAE Systems plans to project images of the surrounding environment back onto the outside of the vehicle -- enabling it to merge into the landscape and evade attack, explained London paper The Telegraph. 

Unlike conventional forms of camouflage, the images on the hull would change in concert with the changing environment, always insuring that the vehicle remains disguised.

BAE Systems is working with an unnamed Swedish company that makes a technology similar to the e-ink screens in digital book readers like the Amazon Kindle and Sony Reader, explained Mike Sweeney, head of external communications for the company.

E-ink screens, as any e-book reader can attest, are both slow to refresh and black and white -- two clear obstacles to this technology. BAE has solved those problems, Sweeney told FoxNews.com.

"The guys in Sweden, together with some other companies we've been looking at, have the answer to that question," he said. BAE is starting with tanks, such as the CV90 (or Combat Vehicle 90, the Swedish equivalent of the Bradley tank) on which the first tests will be conducted. But the technology won't be limited to them, Sweeney said.

"We're also working on it for aircraft," he told FoxNews.com. 

This isn't the first time the technology has been discussed. FoxNews.com wrote about invisible tanks in 2007, when they were merely a concept. And BAE isn't alone in its quest to make things vanish. Several companies have been working on similar technologies, all based on the same approach, as Sweeney was quick to note: They all use "a camera to capture the scene on the other side of the vehicle, then project that image on the other side of the vehicle so that it blends into the environment."

But BAE plans to make it happen, intending to test in Sweden at the end of the month a technology it calls "adaptive signature." And the next stage, Sweeney explained, will be transparent battle armor for soldiers.
More on link


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## Avor (20 Jan 2011)

A very intriguing prospect, but It's hard to imagine it fully intergrated. The cost aside, the practical issues of reliability,durability and maintaince need to be adressed.


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## 57Chevy (20 Jan 2011)

Like it was taken right out of the movie "Predator" with Arnold....
Check out this video entitled Optical camouflage for military troops  :camo:
also this other one entitled Soldier using invisibilty cloak. (Army optical camouflage technology).

A few others at either link.
                                     (Reproduced under the Fair Dealings provisions of the Copyright Act)


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## dogger1936 (20 Jan 2011)

Until the troops hook up their playstations to the invisiable lav to have a 5 on 5 game in the Argandab


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## Edward Campbell (21 Jan 2011)

Technologies of this sort are under development in several places, I think; search here, on Army.ca, for something like "invisibility cloaks." The ideas of _stealth_ and _visual deception_ are attractive - to soldiers who, correctly, value security and surprise, and to vendors who value profits.


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## The Bread Guy (21 Jan 2011)

GAP said:
			
		

> Invisible Tanks, Planes and Armor Could Hit Battlefields in 5 Years
> Article Link
> Published January 18, 2011
> 
> Invisible tanks -- and maybe invisible soldiers -- may soon be charging onto battlefields ....


If they ARE truly invisible, how would we know?


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## cphansen (21 Jan 2011)

metal, noise, heat, motion detectors. How is it different from detecting submarines?

Invisibility cloaks for tanks etc. are not the endall or be all, good troopes used to thinking for themselves will see things like trails being left in snow or sand. It's just another tool in the soldier's arsenal like a ghilly suit.

But it sure looks neat


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## a_majoor (21 Jan 2011)

A different form of "invisibility" is produced through the use of metamaterials (the subject of threads on invisibility cloaks), which have freaky optical properties to redirect waves of light or RF energy around an object, so it effectively does not exist to whoever is looking at it. "Full spectrum" metamaterials do not exist yet, but even eliminating the signature at a particular wavelength would be very disconcerting (the beam from a laser designator is directed around the object, giving you no return, for example. A visible object cloaked in the infra red wavelengths would become invisible to Thermal Imagers and sensors based on that effect).

As noted, the game of offense and defense is ongoing. For anyone who remembers the movie "Quest for Fire", the one group of cavemen hijack the newly returned fire, and one throws a spear to ensure the heroes of the film are out of range. In reply, the intrepid explorers (who found and returned the fire in the first place) fix arrow sized projectiles to Atlatls and shower the hijackers with something resembling an arrow storm, killing them all and allowing the heroes to recover the fire. The arms race dates back to the stone age, and possibly earlier...


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## jollyjacktar (28 Jan 2011)

Shared with the usual caveats.  http://www.aolnews.com/2011/01/27/squid-may-help-make-soldiers-invisible/

Squid May Help Make Soldiers Invisible

For decades, military scientists have tried to figure out the best way to make things disappear, or at least hide them very well.  Members of the U.S. Army's First Earth Battalion hoped to bend physics and render themselves invisible, when they weren't trying to kill goats by staring at them. The British Ministry of Defense's Future Protected Vehicle project wants top tech companies to create an invisible tank, possibly using cameras and reflective screens, to use for patrols in Afghanistan.

But researchers working for the U.S. Navy have found a more down-to-earth -- down-to-sea, in fact -- inspiration in the search for stealth: squid.  Yes, those gentle sea creatures, tasty when deep-fried and served with a piquant marinara sauce, figure prominently in the quest for a real-life cloaking device.  Scientists at Duke University -- something of a hotbed for this kind of work over the years -- the Scripps Institute of Oceanography and the University of California, Santa Barbara's Marine Science Institute are studying the mechanics of how squid, cuttlefish and octopus use special light-sensitive organs and cells to manipulate light and create "dynamic camouflage."

What does that mean? If you've ever gone scuba diving and encountered a cuttlefish, you may have noticed its ability to change color while matching its surroundings, even while jetting along in the water. Its cousin the octopus can even use muscles in its skin to imitate textures, to appear like algae or a rough ocean-reef rock. These chameleons of the sea, called cephalopods, create a range of special effects not just for hiding, but for attracting mates and catching prey.

Cephalopods cast their illusions primarily with organs called chromatophores -- tiny ink sacs controlled by muscles that release pigments in patterns, in layers under the skin. They are among the most intelligent creatures in the sea, and their pattern-making is so advanced they could "probably play a television show on their backs, if their brains were big enough," says Sonke Johnsen, associate professor of biology at Duke University.  "They make color sort of the way soap bubbles do ... but the neat thing about it is they can actively control it."

With $5 million in funding from the U.S. Navy over the next five years, Johnsen is leading a team of researchers trying to determine, in part, whether dynamic camouflage can be put to use on the battlefield.  "The systems evolved by marine animals in order to hunt, hide and mate over hundreds of million years surpass our contemporary engineering designs for underwater vehicles," says one of the team's studies. "The impact will hopefully affect all branches of the armed forces that have aquatic missions. This includes Special Forces, mine hunting vehicles, the submarine community and a newest generation of underwater vehicles that could all benefit from the option of 'stealth.'"

Not just the Navy is interested, either. The Army; defense contractor Raytheon; and the Pentagon's deep-science think tank, the Defense Advanced Research Projects Agency, have funded or are otherwise also involved in the team's work.  They call their primary research tool a Holodeck. But don't think of it in terms of creating Cmdr. Riker-style fantasies -- this Holodeck is about making the animals feel at home.  "We are able to show the animals any scene we want. We have a camera called an Omnicam that takes pictures in all six directions," Johnsen says.  Six monitors -- in essence, plasma-screen TVs -- surround the Holodeck tank, so the team can create a "fairly seamless representation of the world, like being on a coral reef," says Johnsen.  With scientists studying a variety of ways to achieve invisibility, or at least creating the illusion of it, could cephalopods provide the breakthrough? Think twice before ordering that plate of calamari.  "At the moment, what we are left with are the tricks that animals use," Johnsen says. "They are not true invisibility, but they are very good." 


Here is a video from the article showing what they mean, it's fantastic.  http://www.youtube.com/watch?feature=player_embedded&v=7NQUqR_YpsA


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## a_majoor (13 Aug 2011)

All aspect invisibility is becoming closer to reality:

http://nextbigfuture.com/2011/08/invisibility-cloaking-for-whole.html



> *Invisibility cloaking for the whole spectrum*
> 
> A light trajectory is shown against the distribution of the εσ values. The light ray enters the device, completes a loop, bounces off the mirror twice and leaves the cloak with its original direction restored (A). Panel (B) gives a closer view of the vicinity of the inner branch of the cloak. Objects placed within the white region are invisible.
> 
> ...


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## GR66 (7 Sep 2011)

Rather than starting a new thread...

The Americans obviously are not the only ones following this path.

From the BBC website today (Shared with the usual caveats):  http://www.bbc.co.uk/news/technology-14788009

This technology looks pretty impressive.  I'm sure it's pretty darned expensive and I'd imagine it may not be very robust in combat operations.  Rather than using this technology on a large scale to hide an armoured squadron I'd picture it being more cost effective to be used by recce specialty vehicles to target an enemy with stand-off weapons.  You'd need fewer vehicles and they would not be given away once they start firing their own weapons.



Edited to prevent my civilian ignorance from starting a debate about who has the role of calling in air/artillery/other types of beyond-line-of-sight attacks.


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## dogger1936 (26 Sep 2011)

if I ever get one I'm gonna tape some untasteful things to the small camera to project all over my vehicle. Great tech; and I cannot wait to trial it one day!!


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## OldSolduer (26 Sep 2011)

I am looking forward to the day the Stealth Blue Rocket is invented.


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## cupper (26 Sep 2011)

According to some conspiracy theory advocates, the technology has been in use for years now.

Opps, I've said too much, gotta go, the black helos are here. :Tin-Foil-Hat:


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## blacktriangle (26 Sep 2011)

cupper said:
			
		

> According to some conspiracy theory advocates, the technology has been in use for years now.
> 
> Opps, I've said too much, gotta go, the black helos are here. :Tin-Foil-Hat:



I'm pretty sure we already have the technology in the CF. We have loads of AFVs, helicopters, ships and soldiers....you just can't see them!


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## FlyingDutchman (9 Oct 2011)

The Sargent is watching you procastinate.


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## Swingline1984 (4 Jan 2012)

Further development on the concept of an invisibility cloak by "slowing light":

http://www.canada.com/technology/Pentagon%2Bbacked%2Btime%2Bcloak%2Bstops%2Bclock/5946206/story.html


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## Pistos (5 Jan 2012)

Not to be confused with technologies to cloak objects in the infra-red spectrum:
http://www.wired.com/dangerroom/2011/09/invisibility-cloak-tanks-cows/?utm_source=Contextly&utm_medium=RelatedLinks&utm_campaign=Previous

...or technology to cloak objects in the visible light spectrum, aka mirage cloaking:
http://www.wired.com/dangerroom/2011/10/invisibility-cloak-mirage/

I can see future armor combining several upcoming technologies to shield us from prying eyes, and electronic detection.  Starcraft 'ghost' unit anyone?  :nod:


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## a_majoor (6 Jan 2012)

Should be joined to this thread: Metamaterials: a real invisibility cloak http://forums.army.ca/forums/threads/50470/post-446595.html#msg446595


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## Colin Parkinson (6 Jan 2012)

Bah, that's nothing, I have known several Gunners and Bombadiers that perfected vanishing to an art form, You would see them in the morning and then at the end of the day.


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## Swingline1984 (6 Jan 2012)

Thucydides said:
			
		

> Should be joined to this thread: Metamaterials: a real invisibility cloak http://forums.army.ca/forums/threads/50470/post-446595.html#msg446595



Agreed.  One stop shopping for all things invisible (a serious conversation on my work ethic could fit in here).  As an aside, your original thread didn't pop up on my search for 'cloaking device'.


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## a_majoor (26 Jan 2012)

Further advances in cloaking technologies:

http://iopscience.iop.org/1367-2630/14/1/013054/pdf/1367-2630_14_1_013054.pdf

http://nextbigfuture.com/2012/01/experimental-verification-of-three.html



> Three-dimensional plasmonic cloak hides a cylinder from microwaves
> Share
> 
> New Journal of Physics - Experimental verification of three-dimensional plasmonic cloaking in free-space (14 pages) They optimized the cloak design for the 3 GHz range. They have hidden a cylinder from microwaves, demonstrating cloaking of an object in free space, rather than a two-dimensional image. The group has not been able to scatter visible light, but it expects that cloaking small objects is possible. The results pave the way to realistic, practical applications of 3D stand-alone cloaks for radar evasion and non-invasive radio frequency probing.
> ...


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## The Bread Guy (26 Jan 2012)

All the invisibility posts are now here, merged.

*Milnet.ca Staff*


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## OldSolduer (27 Jan 2012)

Colin P said:
			
		

> Bah, that's nothing, I have known several Gunners and Bombadiers that perfected vanishing to an art form, You would see them in the morning and then at the end of the day.


Same for some officers.


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## cupper (27 Jan 2012)

milnews.ca said:
			
		

> All the invisibility posts are now here, merged.
> 
> *Milnet.ca Staff*



If they are invisible, how are we going to read them?


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## a_majoor (23 Feb 2012)

Low cost metamaterials are within reach. Once it becomes practical to make this in bulk many exciting possibilities open up:

http://oregonstate.edu/ua/ncs/archives/2012/feb/discovery-opens-avenue-“negative-refraction”-new-products-and-industries



> *“NEGATIVE REFRACTION” OPENS AVENUE TO NEW PRODUCTS AND INDUSTRIES*
> 
> CORVALLIS, Ore. – Researchers at Oregon State University have discovered a way to make a low-cost material that might accomplish negative refraction of light and other radiation – a goal first theorized in 1861 by a giant of science, Scottish physicist James Maxwell, that has still eluded wide practical use.
> 
> ...



The "other" applications of metamaterials such as super lenses and energy harvesting have applications on the military side as well; high power optics that are much smaller and lighter than existing ones, and the ability to concentrate solar energy to make small man portable collectors that can generate useful amounts of energy when the sun is shining come to mind.


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## a_majoor (14 Sep 2013)

Another group of scientists discovers a simpler method of achievig the effects of metamaterials. Since both metamaterials and this technique uses material science properties to refract the incoming waves in the direction the designers choose, this can be literally "bolted on" to existing vehicles, buildings etc:

http://nextbigfuture.com/2013/09/shaped-teflon-can-hide-objects-from.html



> *Shaped teflon can hide objects from microwaves from one direction*
> 
> Look out for mass-produced invisibility cloaks thanks to an entirely new way of designing and manufacturing them out of materials such as Teflon. The new approach is to create a computer model of the cloak in the form of a conventional material with fixed light bending properties. The model simulates how this conventional material distorts light as it passes by. The computer then changes the shape and topology of the material to reduce this distortion. By repeating this process many times, it is possible to find a topology that minimises the distortion of light so that it remains more or less unchanged as it passes by. The result is an invisibility cloak; not a perfect one but one that can hold its own against many of those made of metamaterials.
> 
> ...


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## Colin Parkinson (24 Sep 2013)

Interesting,  can see the application of this on the upper works of ships, to reduce both the radar and visual signature. As Radar is technical LOS, cloaking the upper works would reduce the "visible" range that you would be spotted, combined with low signature construction, you may have a very hard to detect ship.


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## a_majoor (16 Nov 2013)

U of T discovers yet another way to bend radiiation around an object. there are multiple means to achieve invisibility now, the real question is becoming which one is most robust and cost effective for a particular application?

http://media.utoronto.ca/media-releases/thin-active-invisibility-cloak-demonstrated-for-first-time/



> *Thin, active invisibility cloak demonstrated for first time*
> Posted on November 12, 2013
> TORONTO, ON — Invisibility cloaking is no longer the stuff of science fiction: two researchers in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering have demonstrated an effective invisibility cloak that is thin, scalable and adaptive to different types and sizes of objects.
> 
> ...


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## a_majoor (15 Mar 2014)

More on using these techniques to bend sound. Soon these techniques may have advanced to the point that they can be applied to ships and submarines as well:

http://www.pratt.duke.edu/news/acoustic-cloaking-device-hides-objects-sound



> *Acoustic Cloaking Device Hides Objects from Sound*
> March 11, 2014
> Duke engineers build world’s first 3-D acoustic cloaking device
> By Ken Kingery
> ...


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## a_majoor (4 Apr 2014)

More advances in metamaterial technologies:

http://today.ucf.edu/nanotech-leads-break-stealth-technology/



> *NanoTech Leads to Break-Through in Stealth Technology*
> 
> Controlling and bending light around an object so it appears invisible to the naked eye is the theory behind fictional invisibility cloaks.
> 
> ...


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## a_majoor (19 Sep 2014)

Digital metamaterials promise to open up yet another avenue for the production of "invisibility" cloaks and coatings for equipment and facilities. I have now counted four different means in this thread to create an "invisibility" shield, which means the next huge frontier in military technology will be to discover ways to detect "cloaked" men, equipment and facilities:

http://theconversation.com/invisibility-cloaks-closer-thanks-to-digital-metamaterials-31562



> *Invisibility cloaks closer thanks to ‘digital metamaterials’ *
> The concept of “digital metamaterials” – a simple way of designing metamaterials with bizarre optical properties that could…
> 
> Author
> ...


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## a_majoor (12 Oct 2014)

While very short on details, this is yet another way to make an "invisibility cloak". Metamaterials use precise tailoring of materials, this apparently only needs four lenses:

http://www.wired.co.uk/news/archive/2014-09/29/off-the-shelf-invisibility-cloak



> *Invisibility cloaks built from 'off-the-shelf materials'*
> SCIENCE 29 SEPTEMBER 14  by KATIE COLLINS
> 
> The Rochester CloakUniversityRochester
> ...


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## a_majoor (7 Apr 2015)

Coating submarines and naval vessels in "bubble wrap" to abosorb sound waves. This is much lighter and more efficient than current sound absorbing tiles, and I suspect that is can be much less expensive as well:

http://army.ca/forums/index.php?action=post;topic=50470.50;last_msg=1332344



> *New industrial bubble wrap material and metamaterial for manipulating or absorbing sound for stealthier submarines*
> 
> 1. Current subs use 1-inch-thick rubber foam to reduce sonar detection. Materials scientists at Université Paris-Diderot, the University of Manitoba, and PSL Research University are working on a technique to create a much thinner sheet of rubber populated by thousands of bubbles that work to deflect sonar while saving on weight over the bulky foam. Lab tests have shown that the material cuts down on radar wave detection by 10,000 times.
> 
> ...


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## a_majoor (17 Jul 2015)

NBF on a 3D cloak that works across a wide range of frequencies. If I am reading this right it is prooff against microwaves and sonar, so would make a good all purpose coating for a submarne (invisible to radar when surfaced and invisible to sonar when submerged). The wide frequency range also answers the problem with first generation metamaterials, they were very effective over a very narrow frequency range.:

http://nextbigfuture.com/2015/07/broadband-surface-wave-transformation.html



> *Broadband surface-wave transformation cloak - Molding acoustic, electromagnetic and water waves with a single cloak *
> 
> Two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves.
> 
> ...


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## a_majoor (18 Jul 2015)

More advances in metamaterials. This article describes a one layer "cloak", which is much lighter and simpler than other designs. 
Advances in this sort of design could lead to coverings over vehicles and structures, and eventually uniforms (I want one for parades!)

http://nextbigfuture.com/2015/07/engineers-give-invisibility-cloaks.html



> *Engineers give invisibility cloaks a slimmer design*
> 
> Researchers have developed a new design for a cloaking device that overcomes some of the limitations of existing “invisibility cloaks.” In a new study, electrical engineers at the University of California, San Diego have designed a cloaking device that is both thin and does not alter the brightness of light around a hidden object. The technology behind this cloak will have more applications than invisibility, such as concentrating solar energy and increasing signal speed in optical communications.
> 
> ...


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## a_majoor (7 Sep 2015)

This seems to be a development that is practical for both manufacturing and deployment. Invisible vehicles and systems coming soon...

https://www.hdiac.org/node/2071



> *Bringing Invisibility Cloaks to Reality*
> 
> Researchers are working to create a new design for the Harry Potter-esque invisibility cloak, which will conceal objects, making them more difficult for adversaries to detect.
> 
> ...


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## a_majoor (3 Oct 2016)

Another approach to metamaterial cloaking in radar frequencies.

http://www.nextbigfuture.com/2016/10/metamaterials-for-reduces-reflection-of.html



> *Metamaterials for reduces the reflection of radar might make stealth aircraft invisible to microwaves*
> 
> Iowa State researchers Liang Dong and Jiming Song are working on technology that could someday make a microwave invisibility cloak for stealth aircraft a reality.
> 
> ...


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## a_majoor (20 Nov 2019)

NY Post reports on a practical implimentation of metamaterials from a Canadian company. the vidio is quite impressive:

https://nypost.com/2019/11/15/invisibility-cloak-straight-out-of-harry-potter-is-now-a-thing/



> ‘Invisibility cloak’ straight out of Harry Potter is now a thing
> By Yaron SteinbuchNovember 15, 2019 | 10:50am | Updated
> 
> Forget Harry Potter’s fictional invisibility cloak: A Canadian company that manufactures camouflage uniforms has created a mind-blowing, light-bending material that can make objects seemingly disappear.
> ...


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