First black hole for light created on Earth

[bash]

An electromagnetic "black hole " that sucks in surrounding light has been built for the first time.

The device, which works at microwave frequencies, may soon be extended to trap visible light, leading to an entirely new way of harvesting solar energy to generate electricity.

A theoretical design for a table-top black hole to trap light was proposed in a paper published earlier this year by Evgenii Narimanov and Alexander Kildishev of Purdue University in West Lafayette, Indiana. Their idea was to mimic the properties of a cosmological black hole, whose intense gravity bends the surrounding space-time, causing any nearby matter or radiation to follow the warped space-time and spiral inwards.

Narimanov and Kildishev reasoned that it should be possible to build a device that makes light curve inwards towards its centre in a similar way. They calculated that this could be done by a cylindrical structure consisting of a central core surrounded by a shell of concentric rings.

There's no escape

The key to making light curve inwards is to make the shell's permittivity – which affects the electric component of an electromagnetic wave – increase smoothly from the outer to the inner surface. This is analogous to the curvature of space-time near a black hole. At the point where the shell meets the core, the permittivity of the ring must match that of the core, so that light is absorbed rather than reflected.

Now Tie Jun Cui and Qiang Cheng at the Southeast University in Nanjing, China, have turned Narimanov and Kildishev's theory into practice, and built a "black hole" for microwave frequencies. It is made of 60 annular strips of so-called "meta-materials", which have previously been used to make invisibility cloaks.

Each strip takes the form of a circuit board etched with intricate structures whose characteristics change progressively from one strip to the next, so that the permittivity varies smoothly. The outer 40 strips make up the shell and the inner 20 strips make up the absorber.

"When the incident electromagnetic wave hits the device, the wave will be trapped and guided in the shell region towards the core of the black hole, and will then be absorbed by the core," says Cui. "The wave will not come out from the black hole." In their device, the core converts the absorbed light into heat.

Quick work

Narimanov is impressed by Cui and Cheng's implementation of his design. "I am surprised that they have done it so quickly," he says.

Fabricating a device that captures optical wavelengths in the same way will not be easy, as visible light has a wavelength orders of magnitude smaller than that of microwave radiation. This will require the etched structures to be correspondingly smaller.

Cui is confident that they can do it. "I expect that our demonstration of the optical black hole will be available by the end of 2009," he says.

Such a device could be used to harvest solar energy in places where the light is too diffuse for mirrors to concentrate it onto a solar cell. An optical black hole would suck it all in and direct it at a solar cell sitting at the core. "If that works, you will no longer require these huge parabolic mirrors to collect light," says Narimanov.

http://www.newscientist.com/article/...f=physics-math

[metalhead]

Wow that is insane. I was wondering at first what kind of black hole they were talking about. That is a pretty neat thing they have.

[Morganator]

Wooooooooow! I'm so excited!:yikes This is just awesome! Imagine the implications guys! Free energy for everyone all the time and we can kiss the oil companies good-bye! I am so stoked! They must work as fast as possible to commercialize this and make it available for the mass market!

[Surebrec]

Wooooooooow! I'm so excited!:yikes This is just awesome! Imagine the implications guys! Free energy for everyone all the time and we can kiss the oil companies good-bye! I am so stoked! They must work as fast as possible to commercialize this and make it available for the mass market!

nothing is free. even if they find some way of producing free energy, the end user won't get it for free.

[Bigdoggy]

Wooooooooow! I'm so excited!:yikes This is just awesome! Imagine the implications guys! Free energy for everyone all the time and we can kiss the oil companies good-bye! I am so stoked! They must work as fast as possible to commercialize this and make it available for the mass market!

would never happen, remember we are living in a life where the greedy are greedy. We would pay for free energy because the greedy swine running everything, they need to pay off there $1,000 weekly haircuts, $1,000,000 cars, $50,000,000 houses, etc etc. We would definitely be paying a lot because it's free energy that wouldn't run out.

[Morganator]

nothing is free. even if they find some way of producing free energy, the end user won't get it for free.

would never happen, remember we are living in a life where the greedy are greedy. We would pay for free energy because the greedy swine running everything, they need to pay off there $1,000 weekly haircuts, $1,000,000 cars, $50,000,000 houses, etc etc. We would definitely be paying a lot because it's free energy that wouldn't run out.

Oh, I know! But a man can dream, can't he?

[scottscorpion]

its not a black hole...its just an improved way of collecting light by bending it

and its not really useful yet as it doesnt work for 'visible' light

[zoidy84]

you're right, its not actually a black hole in terms of Black holes in space.

Still cool though!

[Metallica737]

Science is awesome!!!!!!!!!

[Boxman]

I fail to understand how a black hole can create light, when:

- It absorbs light
-Whatever goes in, never goes out.

Anyone willing to give me a science lesson?

[gillmanjr]

I fail to understand how a black hole can create light, when:

- It absorbs light
-Whatever goes in, never goes out.

Anyone willing to give me a science lesson?

I'll try my best (btw I'm an Aerospace Engineer but this black hole stuff is hard for me to get my head around). Here's what I know: first of all a black hole is not really a hole in space. Many people get the wrong impression here because of their name - but despite what everyone thinks a black hole is actually a body in space (just like a planet but much smaller). They just happen to be so dense that their gravitational field is strong enough to attract light and therefore the surface of them appears black. So basically what happens, because the gravity is so strong they absorb everything including matter and energy of all kinds and it just goes towards making the black hole even bigger/more dense. Black holes themselves don't create light but all the matter swirling around them at millions of miles an hour heats up to HUGE temperatures and gives off light and x-rays. In some cases there is so much matter orbiting a black hole that some of it is blasted away from the surface along the polar magnetic field lines.

[Bigdoggy]

Well, I believe that a black hole does have energy in it. I mean, what else acts like a vacuum but doesn't have energy? Every single action in this world and universe has a reaction, be it negative or positive. A black hole that has energy is actually believable. However, the problem is, is how do you extract that energy for it to be useful. That right there is where the challenge is going to be.