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Cheap and scalable invisibility cloaks being developed. The setup is so trivial that I would almost call it a "trick" (as in "Magicians trick"): 6 prisms of n=1.78 glass. Nontheless, it does the job of cloaking an object at visible wavelengths and from several directions.

Is this really new? I don't know, but I know that the original idea of cloaking was pretty different. When cloaking as an application of transformation optics became popular people tried to make devices that work for any incidence angle, any polarization and in full wave optics (not just ray approximation). This is really hard to achieve and I guess that the people that tried to make such devices knew exactly that the task becomes almost trivial by dropping at least two of the three conditions above.

I think it is very easy to call something trivial when you're not the one who invested considerable time (5 min in my case) to design a cloaking device and fill the coffee mugs with water... Also, I did not really violate that many conditions: true I reduced the number of dimensions in which the device works to 1 (as opposed to the 2 dimensions of many metamaterial cloaks). However the polarization should not be affected in my setup as well as the wave phase and wave vector (so it works in full wave optics) - apart maybe from the imperfect lens distortion, but hey I was improvising.

Last year researchers at Imperial College London proposed that along with being used to cloak physical objects metamaterials could also be used to cloak a singular event in time. A year later, researchers from Cornell University have demonstrated a working "temporal cloak" that is able to conceal a burst of light as if it had never occurred.

Using little more than a few perforated sheets of plastic and a staggering amount of number crunching, Duke engineers have demonstrated the world's first three-dimensional acoustic cloak. The new device reroutes sound waves to create the impression that both the cloak and anything beneath it are not there.

and all this without magic metamaterials ...

It's funny to see how people get more and more humble in the desperate attempt to save their stupid ideas... At the beginning was the brave and bold aim to cloak something in free space (in a sphere or a cylinder). This requires inhomogeneous, anisotropic, magnetic materials; hopeless!! So one reduces to one polarization, now we have inhomogenous, anisotropic materials; still hopeless! At this point one downgraded the pretension: instead of cloaking in free space, we make a "carpet cloak" and hide an object behind an invisible dent in a mirror. But if that shall be continuous, we still need inhomogeneity and this is very hard. So now instead of a dent we take a cone and then it is claimed to work ... for ONE polarization. But of course the cloak can't work at all incident angles... irony of fate: everything is now made from birefringent media, the antithesis of what the metamaterials dogma was at the beginning!

Hi Luzi, can you please send me the paper. We are writing a project based on sulfates and carbonates, and all this BS sounds great for the introduction (The authors used Calcite as birefringent material)

Researchers in the US have made a "carpet cloak" that makes objects invisible to sound waves. The device is the first such cloak to work in air and could be used to improve the acoustics in concert halls or even to control unwanted noise.

"...scientists in Germany have built a device that can effectively make objects invisible to sound waves. The performance of the acoustic "invisibility cloak" exceeds that of existing electromagnetic devices and could open up new ways of manipulating waves, including the development of shields against seismic waves."

shit.... they are a few months ahead of us it seems ... :-( what is the impact on our ariadna??

this is what I call truly cloaking!...of course only found in and made by nature :) (video at the bottom of the page)

Definitely beautiful, even psychedelic maybe.. but technically its not really cloaking, you wouldn't call your window a cloaking device right? :)

The video looks surreal!

now active cloaking ... Luzi?, Sante?, Anna?

Old news... Sante was doing this 10 years ago! And why does their metamaterial look like a pyramid?

According to Terry Pratchett pyramids affect the flow of time. Using this, any kind of cloaking device should be trivial.

I think they are taking it a bit too far....

is my memory wrong or isn't this what you have already mentioned as theoretically possible a few years back when discussing this, Luzi?

Very well possible that I mentioned this. In fact I was one of the first who took spacetime transformations in transformation optics seriously. But first, my name is not Leonhardt and I don't work at Imperial, that's why nobody cites me and second I most probably found the idea too stupid to be published. You see the two reasons why I'm not successful in science...

We don't have Science Express subscription here, so I have to wait till the normal paper is out. From what I heard about it, I doubt that this would have made it to Science without the names Pendry and Wegener in the autor list! Certainly, they are two of the smartest guys in Metamaterials, but they are also two of the absolut class A sellers. Pendry by definition is the first in whatever (at least in HIS talks...) but apart from this he's a very nice guy. Better let's not try to characterize Wegener...

An intelligent (that is, self-adaptive) cloak driven by deep learning. Quite cool, eh? Something we can get inspired by?

To keep you updated in the field of metamaterials. "Invisible sensors" are a hot topic at the moment. Of course, mainly due to military applications. Might be interesting to sense something while minimizing the perturbations due to the sensor.

And all seems to be allowed by transformation optics ..... mah

Sante, this thing is made of a superconductor-metamaterial hybrid. Should be non-linear enough for you :)

The device consists of a layer of superconducter, complemented by several layers of metamaterial. And the authors are afraid of potential abuse of this cloak to smuggle forbidden objets on airplanes etc. Hillarious! Another example how good research makes itself completely ridiculous by means of absurd claims about their potential usage.

Electromagnetic analysis of cylindrical invisibility cloaks and the mirage effect

and more invisibility ... have a look at this José! ...

nice presentation...