Chinese scientists create metamaterial black hole
October 16, 2009 by Lin Edwards
(a) A model of black hole composed of a gradient-index metamaterial shell and a lossy dielectric core. (b) Photograph of the fabricated artificial black hole based on metamaterials, which is composed of 60 concentric layers, with the ELC structures in the core layers and the I-shaped structures in the shell layers. Image (c) Qiang Cheng, arXiv paper.
(PhysOrg.com) -- Two physicists in China have used metamaterials to create the first artificial electromagnetic black hole. The scientists, Qiang Cheng and Tie Jun Cui from the Southeast University in Nanjing, China created the tiny black hole in their laboratory, in an experiment that aimed to simulate a black hole.
A black hole is a region from which no light can escape. In space, according to relativity theory, black holes are formed when the space becomes distorted by a large mass, preventing light from escaping its gravitational field, but any region from which no light escapes is a black hole.
The scientists exploited the special properties of metamaterials to create their mini black hole for microwave frequencies. Metamaterials are a class of ordered composites with properties not usually seen in nature. They are known to distort light, and have already been used to create invisibility cloaks that can steer light around an object. The Chinese scientists used their metamaterial to distort microwaves to the extent that those entering cannot escape.
The electromagnetic black hole was built from 60 strips of printed circuit boards coated with a thin layer of copper and arranged in concentric circles. The outer 40 strips form the shell, while the inner strips form the core. Intricate patterns were etched in the copper that alternately resonated and did not resonate at microwave frequency, and which changed progressively from strip to strip.
The scientists measured microwaves going into the device, and found none coming out. The microwaves entering the shell are trapped and guided towards the core, where they are absorbed in all directions equally because of the circular symmetry. The energy absorbed is emitted as heat.
The current device works only with microwaves, but they are aiming to develop a black hole for visible light next. This is more difficult because the wavelength of visible light is much smaller than microwaves, which means the etched structures must also be much reduced in size. Tie Jun Cui said he expected the visible light black hole to be demonstrated later this year.
An artificial visible light black hole could find practical uses in harvesting light for solar cells, and this could mean solar energy could be harvested even in places with diffuse sunlight.
More information: An electromagnetic black hole made of metamaterials, arXiv:0910.2159v1 [physics.optics]
© 2009 PhysOrg.com
Apr 13, 2005 |
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A circular fiber glass cable. The light can get coupled in and can't get out because of the cladding core dispersion.
Finally the light will dissipate in heat I suppose.
Still, it's a step forward in meta-material research.
This research sounds like it is the microwave version of the perfect absorber - much like the work being done at the University of Rochester with visible light.
However, I think "black hole" is a dramatic misnomer.
The research sounds interesting though and could provide new opportunities for experimentation.
http://www.physor...869.html
Actually, I think it's the other way around.
This thing doesn't emit Hawking radiation, for crying out loud. It just absorbs microwaves and emits heat. A pizza in a microwave oven does the same, the difference being that this metamaterial do-hickey is 100% efficient at it.
well, ya, otherwise my microwave oven might swallow the earth when i only intend it to warm my burger..
Seems like an another possible way (when developed) to make a heat source using EMR from the ambient air..!
It's a controlled unidirectional shaped resonant reflector/pathway, dude. No absorption.
MASSIVE DIFFERENCE.
Do not mistake it for anything less than a ~VERY~ incredible device and achievement.
However, now that it has been 'realized', It might be possible for the more ardent 'ground-pounders' (read: Linear-minded limited-vision types..you know, the more outspoken naysayers)
to consider that military black ops skunkworks and other such groups have had such technology for a very long time.
Still not a spacetime singularity, dude.
Also, you can probably obtain the same effect with a larger apparatus made of classical materials. Or paint stuff black for a good approximation. You're not gonna get event horizons and Hawking evaporation either way, though. The evaporation would be quite an issue...
What it does isn't that incredible and doesn't have a lot of immediate applications, it's how it does it that's the really interesting thing. Meta-materials have been around for a relative while, now, there isn't a lot of new physics, but a crapload of engineering potential.
I just think one shouldn't get laymen's hopes high, or scare them, with words like 'cloaking device' or 'black hole'. The exception being the case where doing so nets more research money. That's OK with me.
"What is really going to make your mind boggle is, would you have broken the vase if I had not told you you were going to do it?"