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Light Stopped, Held And Re-emitted By A Crystal
nherc writes: "An article in Nature talks about an incredible new crystal that can actual stop and hold light to be later emitted. It's mentioned light has previously been "slowed" by super cooled gases, but this certainly blows that away. They mention this could be a major step towards quantum computing."
Uerm.. correct me if I'm wrong, but doesn't glow-in-the-dark stuff "stop and hold light to be later emitted"?
optical ram that is a crystal matrix that actually holds the image and energy?
comment directly in my journal
No, really, I know light speed changes. c is just for light in a vacuum... This is really neat stuff, and I hope this becomes a leap forward in understanding quantum mechanics.
Click here or here.
Fucntioned by super cooling a special gas in a chamber, and then shining a specialized laser (yeah, I don't know the specifics) through the gas, opening a pathway through it.
Light was then shined through this pathway, then the laser was cut, "trapping" the light in the gas. What actually happened was that this left an "imprint" in the cooled gas, and when the laser was beamed through the gas again, the imprint of light activated and the beam of light continued.
There was a serious issue with degradation though. The longer the light was trapped in the gas, the poorer the quality the beam of light was when it was reanimated.
Seems like this new method has improved immensely upon that weakness.
Is this basically what the crystal Galadriel gives to Frodo does? Stores light, until it's needed in his "darkest hour?" If it is, it means that those damn elves are still decades ahead of us in technology! We must find them, take their tech, and destroy them!
Colin Winters
...who thinks Galadriel is hot...
The old work was using cold gases--kind of difficult to put into an optical computer. This is using crystals, which is more likely to be practical.
is that they've not only stopped light, but made it go backwards, reversing time, so this 'discovery' got projected into the future, where we're reading about it now as if it were new, altho it's been done some time ago.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
TWW
"Encyclopedia" is to "Wikipedia" what "Library" is to "Some people at a bus stop"
At last, we can get some light into that thing. I was getting really tired of The Dark Crystal
:-)
"I don't know half of you half as well as I should like, and I like less than half of you half as well as you deserve."
...or does the picture at the start of the article make everyone else think of "Missile Command"?
TheFrood
If you say "I'll probably get modded down for this..." then I will mod you down.
The article in Scientific American super cooled gases refers to super cooled gases, not crystals. Like the article says, doing this in a room tempature solid makes it much more feasible for use in solid state computing.
helps to explain how they're achieving this with a graphic representation. Still a little technical for me, but it kinda makes sense.
Your hair look like poop, Bob! - Wanker.
I bet it's the "Quantuim" :)
"a crystal of yttrium silicate containing a few atoms of the element praseodymium"
They need a catchy marketing name... Something like DyLithium Crystals.
Can You Say Linux? I Knew That You Could.
....is of course "Schroedinger's Hammer", but I probably spelled his name wrong.
Infuriate left and right
who the hell keeps rating this down? it was a joke about the silmarils, you philistines! or are you all only capable of fathoming books that have been made into movies?
god is just pretend.
To quote Groundskeeper Willy: "I a-doon't git it."
They 'shackle' the light pulse to an atom so that it can be released later, and all it's "energy is transferred to the electron."?
I thought that could only be done by: causing an electron to jump to a higher orbital (thus higher energy), or adding another electron through ionization.
So can they boost an atom to a higher orbital without filling the lower orbitals? Like bumping an S-1 up to a P-2 or something? Maybe you compare what the energy level is as opposed to what it should be (e.g. three orbitals above normal) and that represents the data (plus spin, too?)
Gee, it's fun to speculate when ZERO DETAILS are given in the article.
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Could this be used to create more efficient solar panels? The photons are converted directly into energy, "stored" in the atoms. Rather than re-release the photons as light, would it be possible to capture that energy and convert it into something more useful?
My understanding of optics is rather lacking... something is nagging at the back of my mind telling me that this wouldn't work...
-- Minds are like parachutes... they work best when open.
Anything that brings us closer to proving Dark Sucker Theory is okay in my book.
± 29 dB
The light is converted to another representation than light inside the crystal, so technically, the light is not being halted. Rather, it is being converted to another form, and then later converted back to light again.
Specifically, "stopping light" has nothing to do with it, though that is what the media in my country keeps calling it.
Bjarke Roune
Only average lightspeed changes. The speed of light (photons - same speed as all massless particles) is always c (about 300kk in m/s). However, the light can be delayed. When a photon hits an atom, it usually transfers its energy to an electron, which jumps to a higher orbital. The electron then nearly instantly drops down to its old orbital and gives off the energy in the form of (guess what) a photon. A constant rate of interception and expulsion by atoms can cause the average speed of the light to be slowed, but the photon is always moving at c. The crystal/laser combination mentioned in the article just keeps the energy from the light a LOT longer than the picoseconds it spends in electrons normally
PUBLIC SPLIT ON WHETHER BUSH IS A DIVIDER -CNN scrolling banner, 10/15/2004
Wasn't there a series of science fictions stories about "Slow Glass" - glass which can hold light for years before emitting it? I love when nature imitates art.
I'm the stranger...posting to
- An electronic delay generator that simply buffers packets;
- Fiber loops.
Fiber loops are better (they introduce no jitter), but more expensive and cumbersome. Maybe in a few years you'll be able to get a short strip of fiber that'll generate tens of milliseconds of delay.I wonder whether there's any signal degradation in the light that passes through the crystal.
-- Stanislav Shalunov
Vietnam aside, I really don't like the chances of any army against one with significantly superior technology - and the US army is heavily trained to rely on the superiority of its tech.
Futhermore, the peaceniks would have a field day with this - I doubt the Elf War would be very popular on the home front. It would take a really strong president to overcome this...
Vote Sauron in 2004!
(This post was a paid message from the Committe to Elect Sauron, a not-for-profit organization dedicated to America's future as the stronghold of the Dark Lord.)
I'm the stranger...posting to
ah!!! see, now that's what i'm talking about -- is it our fault that these jokes are going over the moderator's heads?
god is just pretend.
Stopped? How about 'contained within the crystal substance'.. bouncing around inside.
You guys don't get this, do you? It is not a "light capacitor" or a new twist on "glowies". What has been done here is to use subatomic particles to store information about coherent light signals.
/. geeks remember stirrings that show up from time to time in cyberspace regarding holographic 3D memory. The premise is that, using holographic media, it is theoretically possible to store massive (a terabye in 10 sq. cm) amounts of data in an extraordinarily small space without electron lag which is a problem in high-speed microelectronics.
Perhaps some of the enlightened
In optoelectronic computing systems and quantum computing systems the ability to store photons and photon signals is tantamount to the realization of full scale optoectronic (and quantum-based) computing.
I digress. This is awesome and I am very enthusiastic. Once again, it doesn't stop light, bend time, slow light, warp space or anything else like it. And it doesn't glow in the dark. It's like a single-channel holographic buffer and it is absolutely wonderful!
Vortan out
Knowledge is like ignorance.. too much can be just as bad as not enough.
I'm guessing if it were heavier, the difference would be far too small to measure?
A lot of people have been saying that light only goes at c in a vacuum. This isn't quite right.
Light goes always at c, period. When it goes through a solid, a better metaphor is that it has to slalom around the atoms in the solid. Of course due to QM it's really more like that Charles Addams cartoon with a ski track leading up to a tree, splitting around, and continuing on. At this point, classical approximations stop making sense, and you have to start talking about amplitudes. You can get the Feynman New Zealand videotapes here. It's an excellent but basic and easily understandable introduction to quantum electrodynamics.
In any event, this doesn't seem to be the same mechanism (unless the amplitudes get stuck as if the photon were going in a loop). It appears to be a similar mechanism, as pointed out elsewhere, to glow-in-the-dark paint. Terribly exciting, but not foundation-shattering, unfortunately. It would be a lot of fun if it were.
Another minor wrinkle is that c is very slightly faster than the speed of light in a vacuum, because a vacuum isn't quite empty. Particles come into the vacuum and immediately annihilated each other all the time. You can theoretically get rid of these by putting a vacuum between two plates so close together that these virtual particles can't form.
Contrary to your contradiction, you are wrong.
The speed of light (c) is a very real limitation in the universe, and is *directly* relational to T
Travelling faster than the speed of light away from a given event, yes, would seem to lead you to a place in space where that event had not yet taken place. You are outside the space-time cone of the event.
However.. travelling faster than c WOULD mean you were travelling backwards in time.. at least as far as the math goes.. I'm not sure where you learned that it wouldn't be so. That being said:
You *CANT* travel faster than the speed of light away from the event. It's not just a speed; it's an absolute. c is NOT just 'the speed of light 'particles' in vacuum'. It's the fastest any effect can propagate through the universe; it's *directly* related to Time.
It's *not* the same as the sound barrier. Yes, you may hear an event later, but as with the case of a sniper rifle bullet, you may be dead before the sound reaches you.
You seem to be describing light as an aboslute speed in a newtownian universe. This is not the case.
Space and Time (and hence, speed) are completely intertwined.
It has been done, but not with anything in the "gas" state as is commonly understood. The light-freezing trick was done, IIRC, with a Bose-Einstein condensate. This much-ballyhooed creation is made from a bit of ultracold sodium gas, but it isn't in the same physical state as a gas any more than superfluid helium is.
Scientists restrict study to entire physical universe; creationist
AMD has a quantum CPU almost ready for production. Unfortunately, their trials show that when your cooling fan fails the probability wave collapses and your cat dies.
A man without a God is like a fish without a bicycle.
If we can stop the emission of light and trap the little photons, then what is to say we can't determine their spin, hence have a good look at everyones wonderful quantum encrypted messages. Stuff a crystal of this in the fiber and start to monitor the structure of the data packets, pick out your favourite light encrypted message, pass on, then look at the trail it made.
I'm old, my brain is addled, but being able to stop light, or its immediate emission, has to have counter intelligence uses.
Amazing New Material! Stores Light!!!
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Amazing!!! And not only do they provide light, but heat as well. Buy today. Only $20/piece.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
When the 'material' is beamed with the second laser, it makes the material 'liquid'-like to light, allowing the light to travel through. As the second laser is reduced in energy, the 'material' becomes more and more viscous until it totally absorbs the energy of the light that is in it (becoming 'solid' to light). It stores the light's energy AND it's wave pattern.
Cool idea.
passetspike!
So could I create a laser, fire it into this crystal, then release it later?
Thus putting the massive equipment it takes to generate that laser energy in one place, charging a crystal, put it into my blaster clip, then fire it later?
Can I store light, then later release it into a solar collector or cell? if so this has great potential to be "the perfect" battery.
As I sit here typing, I have about100 other ways this could be used. Time to fire up the ol' patent lawyer!
The Kruger Dunning explains most post on
Were this experiment conducted in conjunction with one measuring the quantum entaglement of those particles in the medium used to "store" the light, I wonder what effect it would have on the spin of the particles on the other end?
A little simpler: a) Quantum entangle the Rb particles (or some of them) with those at a distance. Observe spin.
b) perform this experiment (the one used to "store" light).
c) Observe the spin of the remote particles.
Any change? This would further explain the effects of Quantum Entanglement because not only would the spin of those particles not included in the experiment theoretically change, but one would know it wasn't a change caused by observation alone.
"You are not a beautiful and unique snowflake."...Tyler Durden
How long can they keep the light stopped without too much degradation of the signal?
When his defense asked, "Which computer has Jon Johansen trespassed upon?" the answer was: "His own."
if it is stored in the crystal, and I walk past the crystal, it is no longer traveling a c in respect to my perspective, so wht does this do to relativity?
Will the proton decay?
If light is an effect of another dimension, does the other dimension feel any effect when we stop light?
The Kruger Dunning explains most post on
e=mc2
c is now 0 for this light particle
e=m02
e=m0
e=0
if there is no e, then how do they expect it to "represent" a bit of information?
The Kruger Dunning explains most post on
I'm not sure that quantum computing couldn't somehow benefit from this technology. Typically, you would need the emission (or not) of a photon to represent/detect a quantum state. At some point the system has to resolve and interface to us. I believe that medium is a photon, or series of photons.
The truth is, I'm guessing here, but how else do you build a human interface to a quantum system?
Knowledge is like ignorance.. too much can be just as bad as not enough.
There was also the short story (probably published in F&SF magazine?) where the local bordello went out of business, and everybody bid up the mirrors to amazing prices after hearing a rumor of 'slow glass' type image extraction from antique mirrors...
I do not deploy Linux. Ever.
Is it possible? Can you calculate and model such a thing?
When I first read a story with "slow glass" in it, I thought "That might be cool." Then I thought about how much energy was somehow stored internally if I left a sheet lying in the desert in direct sunlight for ten years. Then I thought about what would happen if all that energy were discharged at once when the crystal structure (or whatever) was damaged by, say, the neighborhood brat throwing a brick through it. And decided that I wouldn't want any of that stuff in my house!
A light pulse that is brought to a standstill is not destroyed. The atoms 'remember' it, so the pulse can be regenerated by changing the intensity of the coupling laser to allow the atoms to re-emit photons - the particles of which light is composed.
This sounds like it came straight out of the a Star Wars technical manual! Maybe when Star Wars Ep III comes out, Lucas will be able make his billions by packaging a tiny lightsaber in every happy meal.
Once upon a time Feanor (employee) created the Silmarils, and they were pretty nice. The gods (management) took notice of Feanor's creation and said, "Hey Feanor, we've got a project for which the Silmarils would come in really handy, so would you kindly hand them over". Feanor then said, "Fuck you, I made these on my own time and if you want them then make some up for yourselves!" The gods then replied, "Were sorry,
but were afraid that were going to have to let you go for your attitude unless you come off of the Silmarils." Feanor replied, "Fine, then let me go." The gods then said, "We'll also make sure that you never work in this town again." Feanor laughed, " Good I don't want to work here anyways." The gods then left Feanor with a final admoninition, " Oh yeah, well see about that! Who will pay you more than we did for the kind of work you do here? You'll really miss the paycheck if nothing else about this job." Feanor was silent; yes he would miss the paycheck, but the Silmarils were worth it!
Actually, I noticed someone earlier [above] saying that the light somewhat went 'back in time'.
This is nothing new as it's be a theory for years that particles move back in time for a moment.
Read more here if you want more info.
It's actually a mind bender, but I haven't read the page above. Another source would be a book called "In Search of Schrodinger's Cat?". A review here.
Other than the Discovery channel crap I studied no Q. Physics. That book was an easy read for anyone who's taken algebra, and I finished it in less than a month. [not bad, I read it when I took a shit... you know]
Get your Unix fortune now!
I actually don't see how this can be applied to quantum computing, yet.
:)
This sounds almost exactly like an optical transistor, except that a transistor actually is an amplifier.
To make it more like a transistor, imagine a 2 part crystal; part A is continually primed to be discharged, laser like. Part B is the light capturing component. A 'gate' laser turns B on and off, an input laser is the signal, and the lazed output is the output.
Quantum computing and quantum mechanics deals with superposition and tunneling, to my understanding, so unless they can feed in 4 inputs, freeze the crystal, and then get one 'correct' output when they unfreeze it, I fail to see how this is quantum.
Given that I described a transistor, I can see this as being critical to an optical computer
Source = input
Gate = freezing laser
Drain = output
You can make an optical and gate this way:
Combine input A and B into one beam. If they are in phase (both true) their output signal amplitude doubles. If they are out of phase (one true, one false) their output amplitude is zero. Pass this combined signal through two crystals.
Pass a *second* 'clock' signal as well that happens to be out of phase and half the amplitude of a true signal. The first crystal fires true when the clock and input signal cancel to produce a '1'. The second crystal fires false when the clock and the input signal combine to produce a '-1'
GPL Deconstructed
so if these crystals stopp light, coudl i cover my car with these and make a clocking device?
It would be really exciting, if thit lets you preserve direction, but it seems to me that combining of the "standing still" and "preserving the direction" is next to impossible.
It'd probably violate the Heisenberg Uncertainty Principle.
If you preserved direction while completely stopping a photon for as long as you wanted, you'd arbitrarily decrease its momentum scalar (you choose the speed of light and therefore introduce real time to a timeless particle). You'd also have all the time in the world to measure its original direction with arbitrary precision (just fire your original photon from a huge distance), and to pinpoint the location of its future emission.
Too much knowledge about both a photon's momentum vector and location = too much knowledge, according to Heisenberg.
But I'm speaking out of pure intuition and not any real physics knowledge, so don't take my word for it.
Uerm.. correct me if I'm wrong, but doesn't glow-in-the-dark stuff "stop and hold light to be later emitted"?
Glow in the dark stuff is made up of phosphors - similar material as what's in your CRT monitor. Phosphors emit visible light when excited.
The phosphors in your monitor are delicately excited by the electron gun in the back. The phosphors in glow in the dark stuff are excited en masse by normal light.
See How Stuff Works for more details.
J.J.
The MPAA announced today that it has worked with the US government to ban light research under the Digital Millenium Copyright Act. A spokes person said "We are happy that we have nipped this little thing in the bud. Controlling light would allow people to create special viewing devices that could delay light at one end and allow people to watch previously 'recorded' films. We think that such a device could even be incorporated into a pair of glasses." They then went on to speculate that quantum computers could be built that were so fast, they could generate DVD decryption keys in fractions of a second, and that there were many other uses that pirates could come up with.
This comment does not represent the views or opinions of the user.
What ever happened to the old idea of "Computer programmers can make viruses, but choose not to". We need to quit making these people celbrities and start going back to the old hacker code of ethics.
So read the link and mod the parent up.
Signed AC because it's more fun ...
Ignore the "p2p is theft" trolls, they're just uninformed
I once read a sci-fi story about some stuff called 'slow glass' which did something like this... it slowed down the light so the photons took about 6 months to get through the glass. The upshot was that you could have a window which looked out onto a midsummer garden in the middle of winter. I never thought they'd actually work out how to do it, though.
Heck, even if they could make it delay only a few seconds it'd make a cool effect!
Hmm.. this is interesting...
Some of you may remember that uncrackable quantum encryption can be created by using a pair of photons. The problem is that the transmitter and receiver would have to be line of sight, or possibly over fiber. I wonder if two of these crystals can be used to trap the photons individually for later analysis.. Don't know if the process of entrapment within the crystal will destroy the quantum effect that makes this sort of crptography possible, IANAQP....
-fc
. echo -e \\04 >
I'm nowhere near qualified to ponder this, but...
If they could store light in a medium, in this case the yttrium silicate crystal, then one other property of light being that it is infinitely compressable, does that mean that we can use that same crystal as a battery that we could charge an infinite amount of energy into? Think laptop battary with the life of 1 year. (Or if the crystal becomes unstable at one point because of the amount of energy in it, make a bomb that releses pure energy and leaves no trace of itself?)
Sometimes I wish I was a plumber, then I'd know how to deal with other people's shit.
I'm sorry, I should update my .sig - wouldn't want the Committee and their Dark Master to be displeased with me, after all. Sauron is seeking the Republican nomination, so Perot's political career will be safe. Until Sauran casts him into the infernal abyss of Mount Doom, of course.
I'm the stranger...posting to
The last science headline that had any science beyond the headline was around the time Neal Armstrong stepped onto a soundstage in the Nevada desert.
If they've actually stopped the light, then the velocity is 0, therefore wouldn't the uncertainy in position be infinite (delta p)*(delta x) > (h-bar), so if that were true, how would you get the light to come back out the same crystal?
I'm not a physicist or anything I just have a high school physics backgrounds, and I'm just wondering.
"Knowledge makes us accountable." - Che Guevara
As you might know from basic physics or chemistry, atoms can only absorb photons of specific wavelengths. In most solids there is sufficient flexibility that it can absorb a significant range of energies, but this still doesn't give the answer.
Light can be thought of as the propagation of transverse electric and magnetic fields (centered on the photon). As they move through a material the travelling fields cause electrons (and atoms) to vibrate in response for a short period of time. However, the material has an inertia and the acceleration of charged particles generates a counter impulse of electric and magnetic fields. The response has exactly the right characteristics to impede the motion of the light's field, but typically at much lesser amplitude. The difference in magnitude of the response explains why light is typically slowed and not stopped.
Oh, and in the case in question, they are presumably converting the energy of the photon into a vibrational excitation within the material rather than an excited electronic configuration.
It's old. 'Crystal Matrix' technology has been used successfully in real military data and power applications for at least a decade. -That's 'real military' as opposed to the highschool production version of it currently unfolding in the Middle East.
From my perspective, I see one aspect of it working like this:
Get everybody addicted to data technology. --Almost done. Note the introduction of the Euro, ("Citizens: To avoid confusion, try to only use credit and debit cards. Thank you. -Yours truly, The New Europe.") and the ever-growing specter of bio-metrics. (Down at my local business supplies warehouse outlet, you can already buy thumb print readers designed to lock all but 'favored users' out of computers or whatever.)
For those of you who don't see why this is bad, consider how much fun it would be to have yourself locked out of the economy for having dissident political views. --Or for failing to pay a traffic ticket. You only get to buy bread if you heartily agree that Arabs are evil. Mm. Fun!
After we spend the next few years allowing this paradigm to settle into place, new computer systems will be introduced which EVERYBODY must upgrade to, and which industry/government will be able to design from the ground up with the objective of making it impossible to flip on your computer without the goons being able to look over your shoulder. -That 'Encrypting Hard Drives' thing from last year? A dry run in order to learn the proper P.R. population handling techniques. They won't screw it up twice, and it's the second time that will count.
Whatever. It's just an elaborate show. Nothing to be scared of. Sit back and enjoy.
As such, being a lover of geek toys, my favorite part about Crystal Matrix technology is its ability to store industrial strength power in very small batteries. --Military vehicles powered by batteries the size of cigarette packs. Neat stuff. Old, but neat.
-Fantastic Lad --"He's just making it up, right guys? He's just crazy, right? Guys. . ?"
Of course we've been using materials that simply *store* and *re-emit* light for a long time (phosphor anybody? glow in the dark?). But I think the real break through here is that these crystals not only store the amplitude of the light, they actually "store" the whole function, so that the same pulses over time can be retrieved. Would this imply a larger crystal could be used for permanent data storage? I can imagine sending one of these things out into space instead of a chiseled plate. It would seem a lot more intuitive than sending, say, a DVD or hard drive ;p
It's 10 PM. Do you know if you're un-American?
Are they really stuck in your memory or are they slowly traversing your brain soon to emerge on the other side...
-- SIGFPE
Yes.. you cannot accellerate past light speed, or even to it. It is asymptotic.
...
However.. if you look on the same graph, something travelling just a bit faster than light would be going backwards in time.
Of course, we would still percieve it as a normal object... so...
I've seen those spontaneous electron/positron pairs described this way
One particle, with the positron being the same electron going 'backwards'. hence the opposite properties).
OK, I'll take that on faith, cause I do not want to strain my brain trying to remember various Minkowsky (sp?) stuff.
The thing that "breaks the rules" is that to some "observers", an object traveling faster than c would be observed to be traveling backwards in time (arriving at one place before leaving the other, for example).
Actually, there is nothing in the theories to prohibit super-luminal motion, however what is prohibited is any super-luminal thing from going slower than c or any sub-luminal thing (like you or me) from speeding up to faster than c.
I think Feynman jokingly proposed this to his thesis advisor one day. As they looked into it a bit more, they didn't find any reason to show that the idea was wrong. One might even be able to imagine that there is really only ONE electron in the universe, just traveling back and forth in time becoming a electron or a positron as it goes along the way.
This last idea doesn't fit well with the evidence of lots more electrons than protons in the universe, but perhaps that evidence is misleading.
Well that is true by definition I suppose.
However, most theories of gravity being seriously studies have changes in gravitation fields propogating at the speed of light.
Since gravity is very weak, it is hard to make measurements about how fast its effects propagate. A fridge magnet can pick up a pin from a table - to pull the pin down to the table via gravity you need to use the entire earth! To make measurements about changing gravitational fields you need to move some very large objects.
To study large moving objects astronomers look at rotating neutron stars and rotating pairs of stars and stuff like that. You might have noticed that there are not very many of those sorts of things in our back yard - so it is challenging to make useful measurements.