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Peeking At The Future: "Perfect Mirror" Cables
sonofpan writes: "About 18 months ago I heard about a few guys at MIT who developed a process for creating a (near) perfect mirror that could reflect many different frequencies at any angle with almost no loss of strength (something that was said to be theoretically impossible). Apparently, they have finally gotten their patents and used the technology to create a dielectric coaxial cable that can transmit light across vast distances and around tight turns with virtually no loss of signal. Read about it at: http://web.mit.edu/newsoffice/ nr/2000/waveguide.html
and the company they started at: http://www.omni-guide.com.
And the original link that described the process and the huge possibilities for its uses is a very interesting read as well: http://web.mit.edu/newsoffi ce/tt/1998/dec09/mirror.html."
"This is going to revolutionize the way people think about confining light." Trapping light invites all sorts of intriguing questions, Fink points out. For instance, if you light a candle in a room lined with perfect mirrors, would the room stay illuminated even after the flame is extinguished? You could try putting a cat in a box of perfect mirrors, getting it to blow out the candle, asking it if it's light or not, and working out if it's dead or alive :) Arieh
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(Sorry, couldn't resist.)
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Multiplexing data over a single fiber is already done with DWDM (Dense Wave Dimension Multiplexing). I have heard of up to 32 colors of OC-192 over a fiber pair in the real world, and over 200 in the lab. It sounds like this new material should be able to push that number even higher. Fiber pairs take up a lot less room than coax though, I wonder what this means in terms of bundling a bunch of them. Another thing to wonder about is if this technology will reduce the number of repeaters needed in a WAN. That's especially important when you talk about areas which are hard to get to, like transatlantic cables.
I'll admit I don't know much about this. Just some casual interest. Anyway, I wrote a paper a while back about quantum teleportation. It's been successfully done with photons. Anyway, quantum teleportation uses something of a "loophole" to teleport the particle (in most cases photons. And no, it's not really a "loophole"..). Won't go into it much but... you're right, the act of observing something disturbs it. Thus you could not have traditional repeaters, that would work by reading and duplicating the signal. QT, tho, doesn't make a measurement at all, thus leaving the data intact. I dunno. This is probably far from feasible now, (and I'm talking out my butt ;) but it was just a thought.. (and as for "Minds, Machines, and the Multiverse.." haven't read it, but if it has a bunch of hooey about multiple dimensions and physics, I dunno if I wanna read it... ;)
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Also of interest, might be the following web-page concerning the research group of one of the principal investigators (John Joannopoulos of MIT): ab-initio.mit.edu.
Actually, when I was at MIT, I took one of Joannopoulos's graduate courses in solid-state physics and can vouch for his teaching abilities in addition to his well-known reputation within the field of electronic structure calculations.
Also of interest might be the webpage of Prof. Tomas Arias at Cornell (whom I work for now), who was a collaborator of John's at MIT up till last year: www.ccmr.cornell.edu/~muchomas.
For a little more background:
Many of the computational calculations that are used by these investigators, in situations like the one where the perfect mirror was postulated, fall into the category of "ab-initio electronic structure calculations". The "ab-initio" part, latin for "from first principles", denotes that the calculations attempt to simulate actual resultant macroscopic behavior from the much more fundamental precepts of the quantum mechanical interactions between the atoms and electrons in the material under investigation. This has some very interesting advantages, not the least of which is that the resulting calculations do not have to justify higher level assumptions, whose applicability might be less assured. That's not to imply that no assumptions are used in this process (if NO assumptions were used, even most modern supercomputers would be unable to calculate the resultant quantities of interest for any more than 4 or so atoms). As it is, typical experiments generally are able to consider 100-150 atoms, which is usually sufficient to determine many properties of interest. The main approximations that are still necessary are the free electron approximation (which mandates that atomic nuclei and core non-valence electrons are immobile compared to the much lighter valence electrons which are important for conduction) and the independent electron approximation (which stipulate that the potential felt by a valence electron is not specifically dependent on the impact of every other electron [as it would be ideally], but is instead affected by a sort-of mean-field approximation of all the other electrons' potentials). However, this independent electron approximation necessitates that the resulting Hamiltonians (energies of the system) must be found by iterative self-consistent methods, whereby each successive output is computationally fed into the algorithm as input until the result converges within certain error limits. The independent electron approximation is usually implemented in terms of either the Hartree or Hartree-Fock theories (in case you want to search for more info).
Anyway, that's all I have the energy to write about, but the websites I spoke of above, probably give links to lots more material. They also have some amazing photos of the ab-initio simulations.
-Daniel
This is the only way I could think of it happening:
The light from a candle (or, actually, probably a laser) would hit a mirror at such at angle that it got reflected back to *almost* the same spot, then *almost* the same spot on the other mirror, and then *between* the first two spots on the first mirror, and eventually it would all be funnelled kindof into one thin line.
Kindof like when we put the automatic pool cleaner in my pool, and at first it works, but then it just goes straight across and back, and we have one clean strip, and crap across the rest of our pool.
This way, the light would never actually hit the candle/laser/whatever.
However, they say it is an *almost* perfect mirror. This means that it's not really perfect, and even if it reflects. 99.999999999999999999% of the light, with the speed that light moves it would all be gone in a fraction of a second. (probalby, it's summer, I refuse to do the real math.)
And, btw, to test if the light was there, you just stick your hand in the box. If there's a blinding flash of light and your hand turns black and charred, it worked.
On their site they mention that their technology, among other things, will exhibit very low attenuation. Low-attenuation fiber was the latest and greatest when China and Japan were laying their fiber. Thinking they were ahead of the game, they laid this stuff, only to find later that low-attenuation cable doesn't carry ITU multiplexed data very well. In low-attenuation fiber, adjacent channels tend to interact with each other, causing harmonic interference at other ITU channels.
Fortunately, most of the fiber laid here in the US is the older, higher attenuation fiber which is great for ITU multiplexed data. As a consequence, the Asian markets have been researching S (short) band multiplexing, because the effects of the low-attenuation fiber are less noticeable at bands outside of the ITU grid.
Doesn't this really mean that we now have a plastic mirror, where before one needed metal like aluminum or silver or stuff to make mirrors?
So now we can have microwaveable plastic containers that are shiny, if IR is allowed through? That we can create a film to place on windows that reflect all the light without using metals such as copper and gold? That we could build LCD displays with this material to provide brighter, thinner, lighter displays?
It isn't just fibers and cables; it really is a mirror, isn't it?
Bye!
GPL Deconstructed
More to the point is that polarization is preserved. Polarization is the primary quantity which is "quantum entalgled" in most current efforts at quantum cryptography, so preserving it is of the utmost importance in making quantum crypto a reality in the near future.
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On their website they claim that they might get even more bandwidth out of a perfect-mirror cable than out of single-mode fiber.
This is all fine, but how are they going to deal with light bouncing back into the transmitter (lasers break when their light is reflected back into them), and the multi-mode characteristic of their cable?
The EM-picture in the first article seems to show a multi-mode characteristic, and because of the mirrors used I see it as a step-index fiber, which can not be used for long-range broadband transmission. Light coupled in at an angle has to travel a longer distance than light that is emitted along the axis of the cable, and so it takes longer to propagate that light.
I'm really not an expert in electro-optics, but could somebody please enlighten me about this?
funded by DARPA and the USAF.
as i recall, one of the major impediments to high power lasers has been energy lost to the amplification mirrors/lenses...major cooling systems to keep them from exploding...plus very heinous alignment issues.
now the USA might be able to use ground based lasers (ala missile command) to protect herself (and the other western democracies) from nuke-wielding totalitarian/terrorist nations.
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See this. at Scientific American.
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Hey, I just realized what this means. If it's reflective on such a wide range of frequencies, that means that the amount of multiplexing data compression you can do is huge.
One of these fibers might be able to carry a hundred times more data then any current fiber, for instance, just by having sub-bands that use different light frequencies. Each band would think they had exclusive use of the superfiber, so they could all be running at max datarate.
..I could use that to download that 100k animated gif on the company website..
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This is exactly what I've been waiting for. Now, I can get that 100 watt CO^2 laser and RTG power source implanted in my midriff and run one of these cables through my arm and to my fingers so I can fire laser beams from my hands!
No need to invest in handguns, spare keys, or window defrosters, I'll just take a finger laser, thank you!
The reason I haven't done this before, of course, is the heat problem with fiberoptics cooking all the musclemeat between the laser and the aperature.
Oh, that and I don't have the millions it'd take to buy the hardware and surgeons needed. But that's hardly the important issue here, is it?
i.e. whatever happened to IBM's laser computing, and micromagnetic disks that stored over 1G?
sell your certainty and buy bewilderment
I always wanted a mirror in which I'd look perfect!
"one treats others with courtesy not because they are gentlemen or gentlewomen, but because you are" --G. Henrichs
Rather than a mirror that can reflect "many different frequencies at any angle with no loss of strength", wouldn't a perfect mirror be one that made you a couple inches taller and dropped 15 lbs?
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Can you imagine a sheet of this stuff on your ceiling?
And wake up every morning thinking a naked fat guy was about to land on top of me? No thanks.
--Shoeboy
OK my physics is garbage, but couldn't a thin sheet of plastic tuned to reflect only wavelengths in the IR spectrum be used for "perfect" thermal insulation?
If so I can't begin to think of the applications this tech could have above and beyond increasing bandwidth.
Maq
| * | | * | * | |
| * * | | * * | * * | |
|** **|*******|** **|** **|*******|
Dispersion makes the pulses to broaden and makes it troublesome for the reciever to detect if there is a pulse or not in the time bin.
| ***| | *** | *** | |
| *** |*** *|** **|** **|* |
|* | *** | | | *******|
Sorry about the figures! The "|" sould really align, forming five time bins.
However there are clever techniques to overcome this problem, for example solitons. A soliton is a pulse that can travel through a fibre without changing shape.
$ cat < /dev/mouse
This is from one of the links off of the article:
Trapping light invites all sorts of intriguing questions, Fink points out. For instance, if you light a candle in a room lined with perfect mirrors, would the room stay illuminated even after the flame is extinguished?
It seems there wouldn't be any way to test to see if the light was trapped inside the room. If you looked inside, some light would escape, and if any energy was exiting the box as a result of the light, then it wouldn't be trapped in the room.
Maybe I'm confusing light & energy here, but if you burned a candle in a box made of this perfect mirror: 1) all of the heat energy from the chemical reaction during burning the candle is released in photons via radiation; which means 2) all of the chemical energy would be converted to photons bouncing around in the box; therefore 3) the box/room would now be a type of battery storing the energy in photons.
So could one create little boxes-o'-light that would have pracitcal uses like a common battery?
I think I'll stop now that I've grossly misused a good number of physics concepts...
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If anyone is interested in the real world implications of this breakthrough, I suggest you check out Mother Earth, Mother Board. Written by Neal Stephenson, it is a rather lengthy article about the difficult process of laying undersea fiber. Part of that difficult is because of the imperfections of today's fiber and the need for signal amplification.
Technology such as this could eliminate the need for periodic repeaters and signal amplifiers, and quite possibly make cable-laying a less complicated proposition.
Who knows, one day soon, our only worries in accessing a trans-Pacific might be the latency inherent in the speed of light! yours,
john
One of the biggest things holding back quantum cryptography is the fact that you can't go but 30km before you lose the signal. In traditional communications you can just use a booster/repeater....but when we are talking about measuring the spins of photons we run into the heisenburg wall. (can't measure something without disturbing it)
Since repeaters would need to measure a photon to recreate it as a stronger signal, this has always been out of the question. But now if we have this cable that can go great distances without repeaters, then we are one giant step closer to quantum crypto.
If you want more info on the subject, I suggest the book "Minds, Machines, and the Multiverse"
--b
Of course, ths is assuming that the rest of the premises is wired to proper cat5 standards, which in the dorms I lived in was far from true. Lots of people abuse UTP because they think wire is wire, but if you look at the cat5 standard it really isn't.
If you break the mirrors will you get 7 regular years of bad luck or 7 internet years of bad luck?
-- You see, there would be these conclusions that you could jump to
Per cost: Until it's massed produced, it's effectively approaching an infinite cost, as it's in the prototyping stage. I don't think anyone can speculate a cost until someone can create a mass-produced version. They don't say how cost effective this material is...
However, unlike current fiber optic technology, this can take multiple wavelengths and multiple polarizations with negligible loss. So in traditional fiber you can only have a beam of wavelength X; in this cable, you can have a beam of wavelength X in 2 different polarizations without problems. Twice the bandwidth now available!
Another benefit is that now you are not limited to a specific spectrum spread by the fiber. You now have access to more or less the entire visible spectrum, plus any other pieces of the spectrum that the cable can reflect perfectly. No clue how big the bandwidth increases with this, but potentially huge!
This technology is an improvement, but it can be used in places where it would be a revolution, not just an evolution. It mentions optical computing, where routing was a problem on a small scale, among other things. It just takes a decent genius to figure out how to use this stuff ^^
Bye!
GPL Deconstructed
If you've got a perfect mirror, give 2 of em to me so I can glue em to the tops of my shoes.
--Shoeboy