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Sci-Fi Science Technology

Slow Light = Fast Computing 134

Posted by Zonk from the yay-light-beams dept.
yohaas writes "The Washington Post is reporting that scientists have been able to slow the speed of light while still maintaining its ability to transmit information. The researchers have even developed a way to 'tune' the process, modulating how fast or slow the light goes within controlled circumstances. From the article: 'Scientists said yesterday that they had achieved a long-sought goal of slowing waves of light to a relatively leisurely pace and using those harnessed pulses to store an image. Physicists said the new approach to taming light could hasten the arrival of a futuristic era in which computers and other devices will process information on optical beams instead of with electricity, which for all its spark is still cumbersome compared with light.'"
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Slow Light = Fast Computing More

Slow Light = Fast Computing

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  • Ahem. (Score:5, Funny)

    by Hawthorne01 ( 575586 ) on Friday January 19, 2007 @12:48PM (#17683500)
    We don't say "slow light" anymore. We say "Luminescentally Challenged".

  • Future performance whores will brag... (Score:5, Funny)

    by Anonymous Coward on Friday January 19, 2007 @12:48PM (#17683504)
    ...in terms of how small their underclock of c is.
  • worst pun ever

  • Hothouse? (Score:4, Interesting)

    by LordPhantom ( 763327 ) on Friday January 19, 2007 @12:56PM (#17683648)
    Well...ok, but...

    Howell and his colleagues created a four-inch-long chamber filled with cesium gas heated to about 212 degrees Fahrenheit.

    I'm guessing that this isn't going to be coming to the desktop anytime soon.... even a major datacenter might balk at the energy costs of doing this versus a parallel traditional solution.

    • Re: (Score:2, Funny)

      by A beautiful mind ( 821714 )
      So it turns out that a slashdot title is a gross oversimplification/mischaracterization of an issue? Say it ain't so!
    • We already have a household appliance that can reach much higher temperatures than that. Just hook your computer up to your kitchen stove and you're good to go!
      • You don't have your kitchen stove on 24/7, however. For servers, that amount of heat for that long would kill a company.

        • Re:Why not? (Score:4, Insightful)

          by ceoyoyo ( 59147 ) on Friday January 19, 2007 @01:58PM (#17684652)
          Why's that? 212F is just the boiling point of water, heating up cesium gas isn't all that hard and you wouldn't need to maintain a very large volume at that temperature. A regular processor will quite rapidly get more than hot enough if you don't spend lots of energy cooling it.

    • I'm guessing that this isn't going to be coming to the desktop anytime soon....

      I don't know about that. Lately I've been looking for a better alternative than my localized, gravinometricly created black hole to slow down light.

    • Just line the chamber with Pentiums.

    • It will have to come to the desktop since we will be running short on electrons soon. Photons, storing bits in single electrons, ... Why do you think all this is being researched these days? They don't want to admit it, but you just have to read between the lines.
    • Every office keeps a coffeepot this hot all day long and no one complains about cost or heat dispersal.

      Of course, you could just run it on a very hot cup of tea*.

      *'Hitchhiker's Guide to the Galaxy' reference.
  • We are already worried about data center power usage. I'm pretty sure it costs a bit to have cesium gas hanging around the data center.

  • reflection (Score:1, Funny)

    by aevans ( 933829 )
    using light to store an image is called reflection. We've been doing it for years.
    • The use of reflection is a relatively new advance in object-oriented programming. This looks like another case where the hardware is finally caching up with the software ;-) BTW, physicists have been slowing light for years, since the speed of light in any media is c/n, where n is the index of refraction.

  • It should be called.... (Score:3, Insightful)

    by julesh ( 229690 ) on Friday January 19, 2007 @01:02PM (#17683764)
    Slow glass [technovelgy.com]

  • Meanwhile, scientists at.. (Score:5, Funny)

    by LM741N ( 258038 ) on Friday January 19, 2007 @01:03PM (#17683790)
    UC Santa Cruz have achieved a 1/1000 slowdown of light by passing a beam through a cloud of marijuana smoke.

    • Re: (Score:3, Insightful)

      by drinkypoo ( 153816 )
      UC Santa Cruz have achieved a 1/1000 slowdown of light by passing a beam through a cloud of marijuana smoke.

      The results were invalidated, however, when it was pointed out that the atmosphere of Santa Cruz is typically a cloud of marijuana smoke, and the control experiment failed to take this into account.

      • Hay Dude, well you know (speaking from 60s experience) measuring anything in a cloud of marijuana smoke is usually a bit slow even when you're allowed to use your digits for math on a computer with an optical modem :: for real dude.
    • UC Santa Cruz have achieved a 1/1000 slowdown of light by passing a beam through a cloud of marijuana smoke.

      Yeah, but I hear they've been doing that since the 60's. :-P

  • The future is now! (tm) (Score:5, Insightful)

    by Itninja ( 937614 ) on Friday January 19, 2007 @01:10PM (#17683876) Homepage
    Physicists said the new approach to taming light could hasten the arrival of a futuristic era
    I hate statements like this. How does a 'futuristic era' arrive? Correct me if I'm wrong, but isn't it impossible to hasten the arrival of the future? And when the future does indeed arrive, will it not then be simply 'the present'?

    • Re: (Score:2)

      by geekoid ( 135745 )
      Clearly slowig down light speeds up time, G'ah.

      It also changegs the behavour in gravity, but you guys have relized that yet.

      -- Futuristic era man.

    • Physicists said the new approach to taming light could hasten the arrival of a futuristic era
      I hate statements like this. How does a 'futuristic era' arrive? Correct me if I'm wrong, but isn't it impossible to hasten the arrival of the future? And when the future does indeed arrive, will it not then be simply 'the present'?
      Not if you can get Doctor Emmett Brown to pomp your DeLorean.

    • Re:The future is now! (tm) (Score:5, Funny)

      by Atzanteol ( 99067 ) on Friday January 19, 2007 @02:16PM (#17684980) Homepage

      And when the future does indeed arrive, will it not then be simply 'the present'?

      Dark Helmet: What the hell am I looking at?!
      Colonel Sandurz: Now. You're looking at now, sir. Everything that is happening now is happening now.
      DH: What happened to then?
      CS: We passed it.
      DH: When?
      CS: Just now. We're at now now.
      DH: Go back to then!
      CS: When?
      DH: Now!
      CS: Now?
      DH: Now!
      CS: We can't!
      DH: Why?
      CS: We missed it.
      DH: When?
      CS: Just now.
      DH: When will then be now?
      CS: Soon.

  • Moo (Score:4, Interesting)

    by Chacham ( 981 ) on Friday January 19, 2007 @01:11PM (#17683914) Homepage Journal
    FTA:

    Howell and his colleagues created a four-inch-long chamber filled with cesium gas heated to about 212 degrees Fahrenheit. When they sent pulses of laser light through that gas, the cesium atoms put the brakes on the leading edge of that wave, creating a photonic traffic jam.
    So Cesium slows things down....

    Yet, this artcle [nytimes.com] which was reported on Slashot here [slashdot.org], says

    In the most striking of the new experiments a pulse of light that enters a transparent chamber filled with specially prepared cesium gas is pushed to speeds of 300 times the normal speed of light. That is so fast that, under these peculiar circumstances, the main part of the pulse exits the far side of the chamber even before it enters at the near side.
    I'm a bit confused. Does Cesium speed thing up or slow things down?

    • Re: (Score:2)

      by julesh ( 229690 )
      I'm a bit confused. Does Cesium speed thing up or slow things down?

      I'm not surprised you're confused. You've read an article on weird quantum effects in the popular press as if anything that was described in it were true. No, light does not travel faster than c in the experiment described. It does do bizarre stuff, though.

    • Re:Moo (Score:5, Informative)

      by exp(pi*sqrt(163)) ( 613870 ) on Friday January 19, 2007 @01:33PM (#17684248) Journal
      The latter article is about phase velocity. Phase velocity is the speed at which the individual peaks and valleys of the signal appear to travel. But peaks and valleys aren't actual 'things' and you can't transmit information using them. (See here [netspace.net.au].) This latest story is about the rate at which you can transmit information, so it's about group velocity [wikipedia.org].

      Despite the fact that the theory was worked out more well over a century ago, almost every modern pop science story about manipulating the speed of light leaves out these crucial points.

      • Re: (Score:3, Funny)

        by shis-ka-bob ( 595298 )
        To strengthen this arguement, the product of the phase velocity and the group velocity is the speed of light squared. Or alteratively, the speed of light is the geometric mean of the phase velocity and the group velocity. So passing the light through Cesium must speed up the phase velocity by the same ratio that it speeds up the group velocity.

        Somewhat off topic... The last page of Physical Review is accelerating down the book shelf at a rate limited by the ability of the physics community to publish pap

      • With slow light it is always the group velocity that counts, so far anyway. What is really exciting is that phase is preserved. Think of how mind bending this is. Applications in interferometry are a very exciting prospect.
        ----
        Discosure: This is a bit of self-promotion here.

    • Re: (Score:2)

      by mr_luc ( 413048 ) *
      That's like asking "does tv make you stupid or smart?"

      Answer: depends.

      I'd answer you in more detail, but I've been watching cable news, so uh ...
    • So Cesium slows things down.... No it causes them to cease (ducks)
    • This experiment appears to be one of a class of experiments that use interference within pulses to generate timing errors that make it look like stuff is traveling at different speeds than it really is. The trick is that the sensor that measures the start and the sensor that measures the end of the pulse aren't really measuring the same thing.

      For example say I generate a one second pulse with my flashlight by pushing the switch on and then turning it off one second later. Since the distance from the filam

      • When I said:

        The trick is that the sensor that measures the start and the sensor that measures the end of the pulse aren't really measuring the same thing.

        I meant to say:

        The trick is that the timing sensor at the entrance of the test chamber isn't measuring the same thing as the timing sensor at the exit of the test chamber.

  • Now we have an explanation for all the Sci-Fi movies where the beam from some "ray gun" is visible (let alone moving at a perceptible speed)! I can enjoy the genre again as this technology provides a way for me to overcome cognitive dissonance!
    • Now we have an explanation for all the Sci-Fi movies where the beam from some "ray gun" is visible (let alone moving at a perceptible speed)!

      Actually, seeing the beam of a "ray gun" is actually fairly plausible: interactions of whatever is being beamed with air. It's quite reasonable for those to be visible and propagate quite slowly.

      Now, I can't help you with space battles.

  • Call me when they slow down darkness. (Score:5, Funny)

    by bad_fx ( 493443 ) on Friday January 19, 2007 @01:20PM (#17684022) Journal
    "No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."

    • Re: (Score:3, Funny)

      by The Darkness ( 33231 )

      "No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."
      Goldstaff, Sorcerer of Light, I will have my vengeance!
  • Three guesses what that image was...
  • Interesting. This is essentially the photon version of AC then. Now, correct me if I'm wrong but:

    1. Change in electric potential means that signals propogate at the speed of light across a chip.
    2. Change in speed of photon would require photon that carried signal (or rather, the "breakpoint" where the speed changed) to travel across a chip.

    Anyone else think that the first actually propogates information *faster* than the second? Now granted, photons are a lot easier to deal with (I've plugged in fiber ca
    • I was under the impression that electrons move significantly slower than light.
      • Electrons in a current (the drift velocity) move significantly slower than the speed of light. The transfer of charge across a conductor is almost at c. This is because, as a potential is applied, then it causes some charge carriers to move. These in turn cause other charge carriers to move, and so on round your conductor, at a much faster pace than your actual charge carrier pace.

  • A much better scientific description here (Score:3, Informative)

    by viking80 ( 697716 ) on Friday January 19, 2007 @01:27PM (#17684144) Journal
    Here is a half decade old article that describes the process well. It also uses units such as nm and Kelvin instead of thigs like "seven times around the earth" and "about 450 degrees below zero"

    http://www.physics.hku.hk/~tboyce/sf/topics/lightf reeze/lightfreeze.html [physics.hku.hk]
  • These types of articles are misleading. The speed of light in a vacuum is c or 299,792,458 m/s. This obviously cannot change. How the slowing of light does occur is not by slowing the photon, but by the electrons interfering with the electromagnetic radiation that is light. This gives the illusion of "slower" light.
    Obligatory Wikipedia article to back me up. [wikipedia.org]
    • The speed of light in a vacuum is c or 299,792,458 m/s. This obviously cannot change. [...] How the slowing of light does occur is not by slowing the photon, but by the electrons interfering with the electromagnetic radiation that is light. This gives the illusion of "slower" light.

      The view that the speed of light in vacuum is any more fundamental than the speed of light in materials is pretty simplistic. After all, we already know that the speed of light in vacuum is not exactly constant [wikipedia.org].
  • Is the light really being slowed down here, or are the photons just taking the scenic route to their destination instead of going in a straight line?

    • Re: (Score:2)

      by donheff ( 110809 )
      That was my question when I read the article. I believe we would be hearing a lot more buzz if a photon actually traveled at less that the speed of light - C is still a constant. When light travels through material like glass (or Ceisium gas) a single photon doesn't "slow down," "bend," or the like. A single photon excites an electron in an atom of the substance causing it to make a "quantum leap." That electron later drops back down to a lower shell releasing another photon. The "slowdown" is in the n
  • (no, not slow Windows--I have that already)

    Could this be used to make a window to look out of that would show me what happened five minutes ago?

    • Just put a mirror on Mars and look at it through a really powerful telescope.
    • I'll give you that window. It's called a webcam, VLC, and a 5 minute buffer. Shesh, anybody can have one of those. I'll make you one myself that is real pretty for a couple grand. LCD or projector not included.

      rhY

  • slowing down the speed of light (Score:3, Informative)

    by ajs318 ( 655362 ) <sd_resp2@earthsh ... minus herbivore> on Friday January 19, 2007 @01:46PM (#17684454)
    It's been done already. Light slows down whenever it passes through anything. It only manages to get up to 299 792 458 ms-1 in a perfect vacuum. Even air slows it a little bit.

    Whenever a beam of light moves from one medium, eg. air, to another, eg. glass, its speed changes. If it enters on the skew, so the speed of one side of the beam changes before the other side, then the beam changes direction; just like a vehicle with a binding brake, it swings towards the side that slows down first. When it comes out of the glass back into air, it speeds up again and changes direction again, exactly the reverse way to what would have happened on the way in (since a beam of light always follows the same path, whichever end it's shining from); unless it's travelling at such an angle there's no way it could ever have got to be travelling in that direction by going through the surface and slowing down a bit sooner on one side than the other. In which case it simply bounces off like a pool ball hitting the cushion and tries to escape somewhere else. This is how fibre optics work.

    It also means that when you blast a pulse of light into one end of a long fibre optic, some of it comes straight along the middle and out of the other end at the speed of light in whatever stuff the fibre is made out of; but some of it takes a longer journey, bouncing off the walls, and some of it bounces more times than others. So you get a longer pulse at the far end than you originally put in (and dimmer, since the same amount of energy is now being spread over more time). If you're sending many pulses at a high enough frequency, there comes a point when the first pulse hasn't finished arriving at the far end before the second pulse goes in, and the receiver won't be able to tell which is which. Also, if the fibre goes through a bend, sometimes some light that you thought was going to bounce off the walls actually strikes at such an angle as it can get out. With modern, highly flexible materials, this can actually happen without you bending the fibre enough to break it.

    If you want maximum bandwidth out of your fibre, you have to take these phenomena into account. You can buy cheap acrylic fibre, with LEDs and phototransistors that screw-couple onto it; these can often be used for RS232 links with no additional components, using the transmitter to light the LED and the phototransistor to pull down the voltage at the receiver, but you'll be lucky to get more than 9600 baud through such a link. With just some simple signal conditioning, you can make it run much faster.

    • Re: (Score:2)

      by sholden ( 12227 )
      It's been done already. Light slows down whenever it passes through anything. It only manages to get up to 299 792 458 ms-1 in a perfect vacuum. Even air slows it a little bit.

      They slowed it to 17m/s (which had been done years ago, the not losing information part might be new?). That's a little different than what air manages...

    • It's been done already. Light slows down whenever it passes through anything. It only manages to get up to 299 792 458 ms-1 in a perfect vacuum. Even air slows it a little bit.

      Well, actually, even a perfect vacuum slows light down a little.

      • Re: (Score:2)

        by ajs318 ( 655362 )
        How so?
        • vacuum contains particles which arise in matter - anti-matter pairs. These may interact with light before the annihilate each other. Or the poster may have been talking about not being able to obtain the 'perfect' vacuum, just a very very low density gas.
        • A "perfect vacuum" isn't empty; it contains virtual particles, and they slow down light a little. It's possible to reduce the occurrence of virtual particles and light then travels a little faster (at least theoretically). It's not useful, but its just one of many illustrations that there is no such thing as a "perfect vacuum".
  • lighting up the PC.

  • ...their computer will never be as fast as Hex.

    +++Out of Cheese Error+++ +++Please Reboot Universe+++ +++Redo from Start+++

  • ...I have to slowly dim the lighting of my room ?!?
  • Now if they can realign the EPS conduits to work with this burgeoning ODN.

  • Implications for cameras (Score:4, Interesting)

    by pHatidic ( 163975 ) on Friday January 19, 2007 @04:14PM (#17687384)
    Does this mean we could take, say, one second worth of light coming into a camera and then slow it down so that we could get a picture at a super high shutter speed at any point during that one second period?
    • I don't have mod points today, but that's one of the most "Insightful" leaps of thought I've ever read on /.

      Kudos to you.
  • The Washington Post is reporting that scientists have been able to slow the speed of light while still maintaining its ability to transmit information.
    Marketing guy: "We can sell the faster light to our customers as an upgrade!"
  • Cesium is the strongest non-radioactive alkali metal. Cesium is also dense enough to sink in water. BOOM!
    Braniac on YouTube [youtube.com]

  • When will somebody figure out how to speed up light such that going for a nice dinner at that quaint little cafe overlooking the crystalline fields on that lovely planet around Tau Ceti is feasible?

  • If you can slow light down, does that mean that if we can slow it to about the speed of a person walking, we'll all gain infinite mass and be incapable of moving any faster?

    Think of the children!

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