RING OF NO RETURN: A cylinder made of metamaterial rings effectively swallows electromagnetic radiation directed toward it in the same plane.
Image: Q. CHENG AND T. J. CUI
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Gravity's Engines
We’ve long understood black holes to be the points at which the universe as we know it comes to an end. Often billions of times more massive than the Sun, they...
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Two researchers say they have built a cylinder that acts as an ersatz electromagnetic black hole, soaking up radiation in the microwave regime like the astrophysical version sucks up matter and light.
Qiang Cheng and Tie Jun Cui of the State Key Laboratory of Millimeter Waves at Southeast University in Nanjing, China, detailed their creation in a paper posted to the online physics preprint Web site arXiv.org last week. Cheng and Cui report engineering a thin cylinder 21.6 centimeters in diameter comprising 60 concentric rings of so-called metamaterials—composite structures specifically crafted to possess unique light-bending capabilities.
Unlike ordinary magnifying glasses, lenses made from metamaterials can have a negative index of refraction, meaning that refracted light bends to the same side of the "normal," the imaginary line perpendicular to the surface of the lens, as does the incident light. In the past few years, research groups around the world have harnessed metamaterials to create "superlenses" as well as for so-called invisibility cloaking, in which light is bent around an object as if it were not there.
The laboratory black hole is based on a similar approach—establishing a graded index of refraction to bend electromagnetic radiation inward to the cylinder's core. The core, in turn, is an efficient absorber of electromagnetic radiation. In one possible application, the core would be replaced with a "payload" such as a solar cell, with the outer layers funneling light inward. But Cui cautions that such an implementation is a long way off, requiring both that the device be modified to work at visible wavelengths and that the two-dimensional ring be extended to three dimensions.
Cheng and Cui's work represents the preliminary realization of a theoretical proposal put forth just this year by Evgenii Narimanov and Alex Kildishev of Purdue University for a metamaterial structure that could absorb incident light from all directions.
Narimanov, a professor of electrical and computer engineering, says that in the wake of his work with Kildishev, as well as the many studies into extreme light manipulation with metamaterials, he is not surprised to see the theoretical made real. "It's impressive, though, how quickly they have done it," he says.
John Pendry, a physicist at Imperial College London who was among the first to harness the unusual properties of metamaterials, says the new research "constitutes an entirely novel way of constructing an absorber, but at the same time keeping control of the absorbed radiation."
Nevertheless, Pendry notes, the analogy to black holes is imperfect. "Black holes absorb incident radiation and other objects, but the key point about real black holes is the prediction of Hawking radiation emitted by the black hole," he says, referring to physicist Stephen Hawking's hypothesis that is rooted both in general relativity and quantum mechanics. Were it observed, Hawking radiation would provide critical insight into the complicated boundary of the two theories. "A real black hole powers the radiation through its gravitational energy," Pendry says, "but the device reported in this paper has no internal source of energy and therefore cannot emit Hawking radiation."
Besides, the metamaterial black hole is not as ruthlessly voracious as the gravitational kind. Cui estimates that the demonstration black hole only absorbs 80 percent of the microwaves that hit it but that increasing the frequency of the incident light—to visible wavelengths, for instance—will increase absorption. Such an artificial black hole for optical light is in the works and might even be developed by the end of the year, Cui says—a prediction that may raise a few eyebrows in the field. "I think that the authors are rather optimistic in projecting into the visible region," Pendry says. "But I would be very happy to be proved wrong."
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24 Comments
Add CommentCongratulations, not on the non-reflecting item, but on creating something in a 3-D universe that is only 2-D. Or, did I miss something? The scientist does say he has to make it three dinensional and that it is only two dinensional now. Which dimension did they eliminate? Thickness I hope, 'cause the world's already got a lot of thick headed......
Reply | Report Abuse | Link to thisx,y,z...right?
Reply | Report Abuse | Link to thisThe renowned ancient Roman philosopher, Counsel, and Senator, Marcus Tullius Cicero, discussed concepts similar to those in the original article in his book, "On Fate". He made it clear , in the same, that you must understand scientific concepts inherent in the structure, physical properties, and physics of the atom to understand how the universe, itself, interacts. Also, he clearly, in this book, defines those basic precepts of logic and reason which, also, must be applied to those concepts. For example, something can not be both true and false at the same time. That is illogical. Sometimes scientists neither consider fundamental concepts concerning the atom itself nor commonly accepts rules of logic and reason in developing theorems inclusive of those involving the "black hole" nor other theorems related to cosmology.
Reply | Report Abuse | Link to thisGod! I wish journalistse would stop calling these things Black Holes they are only photon traps.Putting your salad on a black hole would ruin your entire day.
Reply | Report Abuse | Link to thisMore perfect absorbtion of insolation would be beneficial for pool heating blankets, solar hotwater heaters, etc. You can imagine a couple of jelly fish shaped objects in your pool. A big round top for absorbing radiation from the sun and some long filaments underneath to transfer the heat to the water.
Reply | Report Abuse | Link to this2-D is an approximation they use to describe the properties of extremely thin materials (on the order of 1-5 nm, say). They can get away with this because the thickness of the material is not much greater than the interatomic spacing of molecules in it, so it really does behave in a 2-D fashion. This is an important distinction because at such a size scale, the dominant properties of a material are surface interactions, which are significantly different than lattice interactions of a bulk sample, or any region far removed from a sample's surface. Thus the challenge of transferring the measured behaviors in this article to something of more substantial size.
Reply | Report Abuse | Link to thisCheng didn't say what his black hole could be used for... if it is a super solar panel, that would be great. Could you imagine the electricity that thing could produce?
Reply | Report Abuse | Link to thisVery Interesting technology. I am sure if they get somewhere close to using this to produce solar power they will get a offer from big oil and and coal that they can't refuse. It would be nice to get one big break through that doesnt get co-opted by the oil and coal and lost in time.
Reply | Report Abuse | Link to thisMy hope is that this technology is not bought up by big oil and coal and end up in a warehouse like everything else over the last 20 years. I am sure if they realize their vision and can focus this on solar energy they will get an offer they can't refuse from the big boys who will never let this see the light of day.... so to speak
Reply | Report Abuse | Link to thisIt would produce the same electricity as any other solar panel. Namely, a theoretical maximum of 1330 watts per square meter of collecting surface. Because that's all the energy that is there to collect.
Reply | Report Abuse | Link to thisYour tin foil hat has slipped. You might want to see to it.
Reply | Report Abuse | Link to this@frgough:
Reply | Report Abuse | Link to thisThat would be true if any modern solar cells produced even close to the maximum allowed by the incoming energy. What JamesDavis meant was having much more efficient solar cells and technology would be nice. Approaching that 1330watts/sq m would be a great thing for consumer electricity production.
Just what good is it? You can get the same eff from standard collectors.
Reply | Report Abuse | Link to thisThis sounds like scalar microwave electromagnetics, the Tesla concept of producing vast amounts of "free energy" by charging atoms in a vacuum. Have the Chinese perfected a "directed energy" Doomsday weapon?
Reply | Report Abuse | Link to thisThe problem with current solar cells is not so much absorption of available light as it is the transport of generated current. Which is capped at about 14-21% at maximum output due to limitations in conductivity and storage.
Reply | Report Abuse | Link to thisOps ... in SCIAM I have not expected such an analogy .. I think we do not need scientists to tell you that that was no way a black hole.
Reply | Report Abuse | Link to thisIf that was one then with refraction and absorption technique lot of different types of black holes could be created
:)
This could be used for efficient heater exchanger or photovoltic research ... :)
Reply | Report Abuse | Link to thishttp://joydip.blogspot.com
To Mister A:For over a decade I have called for the term to be reflective of the quandry it truly presents and that is a point of gravitational infinity or Ginfins for short.
Reply | Report Abuse | Link to this.To Ufologist:And this device increases the amount of energy hitting and being absorbed by the water's surface how exactly?
.To Galaxy_man: Nowhere does it say they have accomplishedthis structure manufacture at the single atom high thickness, and, thickness is still thickness whether attributed to a molecule or a skull.
.It definitely has an application if you DON'T want energy to effect some surface such as spacecraft or asteroids being pushed long term by the sun's out put, making orbital models that will not vary with time.
. When they dig down to the center what do they find? No answer is given to that obvious question.
.I have wondered if M=E/(c**2) and you could keep pumping say,2 gigahertz into a single point, eventually you would generate some mass, and what would the nature of that E specific Mass be? An electron? A neutron? If you hit it with 1 gigahertz and 4 gigahertz what different type of matter would you produce? This disk seems like the perfect labratory to find out the answer.(Oh hell, quantum physics tells us we wouldn't be able to measure the result).
You strike me as the kind of person less interested in real answers than in upsetting a lot of people.
Reply | Report Abuse | Link to thisGalaxy_man, don't trip on your cape. wouldn't want to damage a fine specimen.
Reply | Report Abuse | Link to this.I do offer construtive ideas about it. Did you see your name and had to lash out? I said it has applications for surface protections where little else works effectively both physically and financially , in space on probes or habitats. The ISS should be coated with them to ward off the effects of solar storms.
. I said these may be the perfect labs to study if Einstein's theory works backwards, which is a dam good thing to investigate not whether it could heat a pool. And wouldn't you get electrocuted in a pool using such devices? What if we dicover that pumping 4.5 gigahertz into one creates anti-protons? think of the advantage if there was no need for expensive and ineffective magnetic bottling but could harbor enormous quantities in a disk like a frisbee?
I think my statement of two dimensionality is pertinent. They do not say it is one atom thick. Why not let them defend themselves. And instead of attacking me, why don't you come up with a beneficial use for it as it is. They make creams to treat that itchy...
And Galaxy_man perhaps thes objects will also prove to be the future way that solar voltaic cells are made! Imagine one that gave you 100% effective harvest of the incident waves!
Reply | Report Abuse | Link to this.We could power the ISS with one the size of that swimming pool as opposed to the soccer field we have extended now.
I'm surprised no one has mentioned the inevitable military applications for a sort of microwave "black hole". RADAR Is actually microwaves. such a technology, If truly applicable, would absolutely and unconditionally trump any current RADAR absorbing materials. I am glad this technology or at least research has been shared amongst the materials science community instead of being pigeon holed into a technological arsenal of war.
Reply | Report Abuse | Link to thisBut you will find that the material absorbs a very small range of microwave frequencies, meaning the use if it as a stealth coating would be a waste of money and add weight to something you'd like to go faster. No, it's surprising that the Power industry hasn't squashed tis science in its infancy. If we replaced only our southfacing windows with a material that changed 100% of the incident energy into electrons, we could get off the grid. Oh, yeah the gtid that is expecting to have an infusion of a trillion dollars of taxpayer dollars to upgrade it. The other use of a trillion, i.e., develop the metamaterial, would be a wiser investment but comes with no margin or shareholder profit.
Reply | Report Abuse | Link to thisI put my penis in a black hole once.
Reply | Report Abuse | Link to thisI liked it.