Invisibilty cloaks

[dragon]

Not quite but one step closer.

In an important step toward the development of practical invisibility cloaks, researchers have engineered two new materials that bend light in entirely new ways. These materials are the first that work in the optical band of the spectrum, which encompasses visible and infrared light; existing cloaking materials only work with microwaves. Such cloaks, long depicted in science fiction, would allow objects, from warplanes to people, to hide in plain sight.

Both materials, described separately in the journals Science and Nature this week, exhibit a property called negative refraction that no natural material possesses. As light passes through the materials, it bends backward. One material works with visible light; the other has been demonstrated with near-infrared light.

The materials, created in the lab of University of California, Berkeley, engineer Xiang Zhang, could show the way toward invisibility cloaks that shield objects from visible light. But Steven Cummer, a Duke University engineer involved in the development of the microwave cloak, cautions that there is a long way to go before the new materials can be used for cloaking. Cloaking materials must guide light in a very precisely controlled way so that it flows around an object, re-forming on the other side with no distortion. The Berkeley materials can bend light in the fundamental way necessary for cloaking, but they will require further engineering to manipulate light so that it is carefully directed.

One of the new Berkeley materials is made up of alternating layers of metal and an insulating material, both of which are punched with a grid of square holes. The total thickness of the device is about 800 nanometers; the holes are even smaller. "These stacked layers form electrical-current loops that respond to the magnetic field of light," enabling its unique bending properties, says Jason Valentine, a graduate student in Zhang's lab. Naturally occurring materials, by contrast, don't interact with the magnetic component of electromagnetic waves. By changing the size of the holes, the researchers can tune the material to different frequencies of light. So far, they've demonstrated negative refraction of near-infrared light using a prism made from the material.

Researchers have been trying to create such materials for nearly 10 years, ever since it occurred to them that negative refraction might actually be possible. Other researchers have only been able to make single layers that are too thin--and much too inefficient--for device applications. The Berkeley material is about 10 times thicker than previous designs, which helps increase how much light it transmits while also making it robust enough to be the basis for real devices. "This is getting close to actual nanoscale devices," Cummer says of the Berkeley prism

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[Ford Prefect]

In an important step toward the development of practical invisibility cloaks

There is something very wrong with this sentence.

[Broomstick]

Oooo - not just visible light but near-infra-red! Wouldn't that mess up thermal imaging?

[nickolay1]

Oooo - not just visible light but near-infra-red! Wouldn't that mess up thermal imaging?

Thermal imaging is far to mid infrared.

[GrandMasterTerwynn]

Oooo - not just visible light but near-infra-red! Wouldn't that mess up thermal imaging?

Thermal imaging is far to mid infrared.

If they can do near-IR, then mid- to far-IR is a piece of cake. Not too long ago, they were tickled that they could do it for microwaves. It's when you get down into the shorter wavelengths of visible light that building meta-materials starts to become a real bitch.

[Fingolfin_Noldor]

I talked to someone about this negative refraction thing. In practice it's pretty possible to create a broadband metamaterial to do the job, but it's incredibly difficult. It involves how the birefringent material are arranged just so that the job can be done.

[Darth Wong]

People are too eager to think that this will be like something they've seen in sci-fi. Let's be realistic about this: they can't even make a perfectly distortion-free mirror or telescope lens. They might be able to make something you can't pick up from far away, though. But the idea that people will bump right into something without seeing it was there ... well, that's just silly.

[RedImperator]

Oooo - not just visible light but near-infra-red! Wouldn't that mess up thermal imaging?

If I understand correctly, this material won't do a thing to light which emanates from within the cloak (other than the usual distortion/absorption effects that any material will have on light). So soldiers couldn't wear a cloak and turn invisible to thermal imaging.

[Admiral Valdemar]

People are too eager to think that this will be like something they've seen in sci-fi. Let's be realistic about this: they can't even make a perfectly distortion-free mirror or telescope lens. They might be able to make something you can't pick up from far away, though. But the idea that people will bump right into something without seeing it was there ... well, that's just silly.

Which is why this will likely look more like the cloaks used by Predator Yautja warriors or Section 9's Maj. Kusanagi etc. You won't have a perfect nothingness, but you will have something that should be practically impossible to spot when not moving and at several metres or more.

If I understand correctly, this material won't do a thing to light which emanates from within the cloak (other than the usual distortion/absorption effects that any material will have on light). So soldiers couldn't wear a cloak and turn invisible to thermal imaging.

There are suits today that can essentially block most IR emissions from a human, so long as they don't mind heating themselves up in the process. Of course that wouldn't be very practical for long durations given the heat a human body can put out.

[salm]

Oooo - not just visible light but near-infra-red! Wouldn't that mess up thermal imaging?

If I understand correctly, this material won't do a thing to light which emanates from within the cloak (other than the usual distortion/absorption effects that any material will have on light). So soldiers couldn't wear a cloak and turn invisible to thermal imaging.

Question is, is thermal imaging that important? Modern Armies who are going to be equipped with this sort of thing are nowaday mainly fighting against dirt poor and under equipped guerilla forces, like in Afghanistan for example. I doubt that many guerillas are equipped with thermal imaging devices. I guess something like this could be very usefull for such tasks.

[Broomstick]

No? Are there not thermal imaging cameras available on the civilian market? Do you think guerrillas would not try to obtain either those or military grade?

I actually don't know how important thermal imaging is these days, it was just a thought that occurred to me.

[Singular Intellect]

Which is why this will likely look more like the cloaks used by Predator Yautja warriors

That sure as hell would make paintball more interesting!

But seriously, even a cloak resembling the Predator effect would be an amazing feat.

[salm]

No? Are there not thermal imaging cameras available on the civilian market? Do you think guerrillas would not try to obtain either those or military grade?

I actually don't know how important thermal imaging is these days, it was just a thought that occurred to me.

Sure they would try to obtain them and some would probably manage to but i doubt that they'd have the resources to fit very many of their troops with these devices. And if they manage to do so they still have to invest resources which they then don't have to buy explosives or ammo.

I'm not sure about this though. That was really just a guess on my part.

[Fingolfin_Noldor]

Question is, is thermal imaging that important? Modern Armies who are going to be equipped with this sort of thing are nowaday mainly fighting against dirt poor and under equipped guerilla forces, like in Afghanistan for example. I doubt that many guerillas are equipped with thermal imaging devices. I guess something like this could be very usefull for such tasks.

Er yeah, it is important. How do you expect people to see at night?

[cosmicalstorm]

Sure they would try to obtain them and some would probably manage to but i doubt that they'd have the resources to fit very many of their troops with these devices. And if they manage to do so they still have to invest resources which they then don't have to buy explosives or ammo.

I'm not sure about this though. That was really just a guess on my part.

I recall that Hezbollah caused a lot of trouble for the israelis back in 06 using counterfeit israeli military uniforms, using night-vision gear and what not so I wouldn't rule it out completely.

[Broomstick]

Question is, is thermal imaging that important? Modern Armies who are going to be equipped with this sort of thing are nowaday mainly fighting against dirt poor and under equipped guerilla forces, like in Afghanistan for example. I doubt that many guerillas are equipped with thermal imaging devices. I guess something like this could be very usefull for such tasks.

Er yeah, it is important. How do you expect people to see at night?

Do "night vision goggles" use thermal imaging, or do they somehow amplify ambient light? I don't know much about the details of such technology.

[Singular Intellect]

Do "night vision goggles" use thermal imaging, or do they somehow amplify ambient light? I don't know much about the details of such technology.

Your typical night vision goggle just amplify existing light (like starlight, moonlight, etc).

[loomer]

The eventual development of 'cloaking gear' will be of use only to two groups.

Special ops groups, and voyeurs. Sometimes they're one and the same, too!

[GrandMasterTerwynn]

Do "night vision goggles" use thermal imaging, or do they somehow amplify ambient light? I don't know much about the details of such technology.

Your typical night vision goggle just amplify existing light (like starlight, moonlight, etc).

The cheapie first-generation night vision devices are also sensitive to near-IR, so they could both collect ambient visible light, and could use a near-IR illuminator when the amount of ambient visible light just isn't doing it.

[salm]

Question is, is thermal imaging that important? Modern Armies who are going to be equipped with this sort of thing are nowaday mainly fighting against dirt poor and under equipped guerilla forces, like in Afghanistan for example. I doubt that many guerillas are equipped with thermal imaging devices. I guess something like this could be very usefull for such tasks.

Er yeah, it is important. How do you expect people to see at night?

That's not how i meant it. I meant that guerillia forces can probably not afford to buy these thermal imaging devices so if the modern armies of today are equipped with invisibility cloaks and can only be seen by thermal imaging it doesn''t matter because the guerillas do not have thermal imaging.

[PeZook]

Unless manufacturing techniques can keep up, we're not gonna see regular soldiers wearing anything resembling an "invisibility cloak", since it's so motherfucking expensive. Also, it's not like we actually need it for many tasks when fighting guerillas: snipers would love it, maybe we could equip some UAVs with it if we need to violate somebody's airspace.

The microwave- and light-bending materials would be awesome to use on things like tanks, though, to make them more surviveable against helicopter gunships, missiles and other tanks. But of course we run into the same problem: price. If you can buy a company of tanks for the price of fitting one with superstealth armor, then it's kinda moot to use it.

[salm]

Unless manufacturing techniques can keep up, we're not gonna see regular soldiers wearing anything resembling an "invisibility cloak", since it's so motherfucking expensive. Also, it's not like we actually need it for many tasks when fighting guerillas: snipers would love it, maybe we could equip some UAVs with it if we need to violate somebody's airspace.

The microwave- and light-bending materials would be awesome to use on things like tanks, though, to make them more surviveable against helicopter gunships, missiles and other tanks. But of course we run into the same problem: price. If you can buy a company of tanks for the price of fitting one with superstealth armor, then it's kinda moot to use it.

Wouldn't regular soldiers love it too? I mean if you are invisible you can patrol cities without being shot at and things like that. Also, guerillas wouldn't know that you are currently standing on one of their remote controlled bombs so they wouldn't pull the trigger.
These cloaks would also be very good for spies and recon units.

I#m not so sure about tanks since tanks can allways be identified because you can see the tracks they leave.

[PeZook]

Wouldn't regular soldiers love it too? I mean if you are invisible you can patrol cities without being shot at and things like that. Also, guerillas wouldn't know that you are currently standing on one of their remote controlled bombs so they wouldn't pull the trigger.
These cloaks would also be very good for spies and recon units.

Oh, I'm sure they'd love them, but they're not going to get them any time soon.

Of course, part of a patrolman's job is to deter attacks and keep up a presence, so being visible may in fact be essential to it.

As for spies, well, spies never do the James Bond style "break into a secure facility and steal important doodads" thing anyway

Reconeissance, observation and the like would of course be the ideal place to use tech like this, where you have to stay in one place undetected for hours or days at a time.

I#m not so sure about tanks since tanks can allways be identified because you can see the tracks they leave.

They can be identified, but they can't be shot at. If an ATGM warhead won't see the tank (or what it thinks a tank should look like), it can't hit it, now can it?

[Fingolfin_Noldor]

The soldiers are just going to hate it if the material involved is incredibly hard to maintain. Nonlinear crystals and the like are incredibly fragile, to say nothing of the difficulty involved in growing them.

[Sarevok]

Hiding TANKS ? Lol. That's like training an elephant in ninja stealth and sending it to assassinate someone in a glass palace filled with squeaky rubber balls. Instead of Future Tek level 3 it would be better spend defense budgets on pre existing ATGM countermeasures. Like the Israeli Trophy for instance.