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Fastest-Ever Flashgun Captures Image of Light Wave

Posted by ScuttleMonkey on Fri Jun 20, 2008 12:48 PM
from the fastest-flash-in-the-west dept.
Science Technology
loconet writes to tell us that a team of researchers have created the shortest-ever flash of light. Weighing in at just 80 attoseconds, this flash has already been used to capture an image of a laser pulse and could possibly be used in the future to capture the electron movement around large atoms.
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Submission: Fastest-ever flashgun captures image of light wave by loconet (415875)
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  • Who woulda thought? (Score:5, Funny)

    by rumblin'rabbit (711865) on Friday June 20 2008, @12:50PM (#23875979) Journal
    My God, James Clerk Maxwell was right after all!

  • Duckhunt (Score:4, Funny)

    by AioKits (1235070) on Friday June 20 2008, @12:51PM (#23876003) Homepage
    Can I get one of these flashguns for that? I'll show those ducks who the boss is!

    • Re:Duckhunt (Score:5, Funny)

      by andrewd18 (989408) on Friday June 20 2008, @12:54PM (#23876049)
      Newsline Saturday: Hundreds of mallard ducks found dead outside residential area; experts believe death caused by epileptic seizures.

      • Re:Duckhunt (Score:5, Funny)

        by PawNtheSandman (1238854) on Friday June 20 2008, @01:06PM (#23876231)
        What's the difference between you and a mallard with a cold?

        One's a sick duck and... I can't remember how it ends, but your mother's a whore.

        • My girlfriend tells a joke about ducks. It goes:

          "What's the difference between a grape and a duck?"
          Answer: "Both are purple, except for the duck."

          Yeah, it's stupid, but I laugh, and then she has sex with me.

  • Sounds impossible (Score:4, Insightful)

    by Carewolf (581105) on Friday June 20 2008, @12:54PM (#23876051) Homepage

    Using light to take pictures of light in motion?

    This is either a hoax, or the the article is skipping some really important part.

    • Yep, it's hoax. (Score:5, Funny)

      by Anonymous Coward on Friday June 20 2008, @01:00PM (#23876143)

      It is a hoax. see the picture of the light pulse? Well, for one, it's only showing a wave and we all know from physics that light is both a wave and and particle. So where's the particle? Hmmm?

      Secondly, the wave is, well, wavy. And we know, again from physics, that light only travels in a straight line.

      Those damn scientists always trying to fool us! And engineers too!

    • Re:Sounds impossible (Score:5, Interesting)

      by bugnuts (94678) on Friday June 20 2008, @01:01PM (#23876163) Journal

      from TFA, I believe it's imaging a laser pulse shot through neon gas. It's the laser pulse that triggered the flash in the first place.

      Bizarrely, the article states

      As each flash is intense enough to completely ionise a neon atom and release an electron, the researchers could use those electrons like a flashgun, to illuminate some of the original 2.5 femtosecond trigger pulses of laser light.
      This is interesting, because the neon is releasing electrons, not photons.

      I agree that snapping a photo of light sounds dubious, but it looks like an electron flash, so maybe it's just making something visible that wouldn't have been seen otherwise.

  • Um... What? (Score:5, Interesting)

    by barfy (256323) on Friday June 20 2008, @01:06PM (#23876233)

    Ok, Internet Physicists out there, please help me.

    Ok, first you have this coherent photon beam. This means that they are all traveling at the same direction. So how do you take a picture of THAT?

    You are bombarding the photon beam with photons, are the photons opaque, reflective, or TRANSPARENT? How do the photons from the flash, BOUNCE BACK at the camera. When they bounce back, how do you get color?

    Is it just me, or does this make any sense at all?

    • Apparently it's not a flash of photons, but a flash of electrons.

      Maybe it's measuring the magnetic deflection? I know that both photons and electrons can be moved with a charge, so they may have an effect on each other.

      If you remove the scatter and noise, you can probably get a pattern of electrons passing by photons ... but I am not a physicist!

    • Re: (Score:2, Informative)

      by Benbrizzi (1295505)
      That's not what happens. You only see a laser because the photons reflect off particles (neon in this case). The photons which hit your camera all come from (almost) parallel lines so what you see is where the photons hit by your beam were.

    • Re:Um... What? (Score:5, Informative)

      by Btarlinian (922732) <bjcbell&gmail,com> on Friday June 20 2008, @01:31PM (#23876595)
      From the article it sounds like a pump-probe experiment. They excite the neon with a 2.5 femtosecond pulse and then image the excited state with a 80 attosecond pulse. (You obviously need the imaging pulse to be shorter than the excitation pulse.) I'm not sure how much detail you would be able to get from this though, as the wavelength and brightness of the light source would be a limiting factor.

    • Re:Um... What? (Score:5, Informative)

      by againjj (1132651) on Friday June 20 2008, @01:53PM (#23876941)

      Ok, first you have this coherent photon beam. This means that they are all traveling at the same direction. So how do you take a picture of THAT?

      In a different way that a standard photograph.

      You are bombarding the photon beam with photons,

      No, you aren't. That doesn't make sense.

      What they do is have the laser pulse travel through something they call a "chirped mirror". This packs the photos from the laser pulse into a smaller space. This then travels through a neon cloud, which then creates a flash of light. This flash of light is the "shortest-ever flash of light".

      To photograph this flash of light, they direct it into a second neon cloud, which ionizes atoms, releasing electrons. Those electrons are then recorded. Multiple flashes were required to produce enough electrons to build up the image shown in the article, so what you really have is an image of many flashes overlaid.

    • Re:Um... What? (Score:4, Insightful)

      by barfy (256323) on Friday June 20 2008, @02:04PM (#23877087)

      Thanks, but I think there is something I have hopelessly never figured out, and that something would also let me understand how reflection works. How does an atom know the direction that the photon was traveling and and what does it bump off of? And isn't the atom round, so how come reflection works like the atoms are a plane. And how does the atom know the relative position of the atoms around it, so that it can reflect the photon in the right direction?

      This is also the problem with lenses. How does the atom know the surface of the greater object, so that it knows what directions to send the photons that are passing through?

      I am sure if I understood this, it would make the underlying question here easier. But as many of these answers so far show, this is be far, not a trivial question.

      • Re:Um... What? (Score:5, Interesting)

        by TigerNut (718742) on Friday June 20 2008, @02:33PM (#23877433) Homepage Journal
        Richard Feynman once pondered, if moisture molecules in the atmosphere scatter light, and presumably this is a random effect because the molecules are randomly distributed, why is it that buildings, etc. when they're viewed through mist, do they still have sharp edges? You'd think all the random scatter would blur the edges.

        That thought train led him to do some fundamental work in particle scattering and path integrals, IIRC, and eventually to the Feynman diagrams that are now commonly used to describe some aspects of particle interactions.

        So you're thinking some good deep thoughts there, but I can't give you a good answer other than "they just know". Basically the "proper" reflection is the only one that is coherent to the observer and the other reflected beams are all out of phase so they might as well not happen... and therefore they don't. Or something like that.

        • Re:Um... What? (Score:4, Funny)

          by Anpheus (908711) on Friday June 20 2008, @04:50PM (#23879669)

          God dammit, now what's the answer? Why are the building edges sharp?

          Feynman would never have left me hanging like that.

        • Re:Um... What? (Score:4, Informative)

          by BlackLungPop (1307317) on Saturday June 21 2008, @11:26AM (#23885989)
          Check out the book QED: The Strange Theory of Light and Matter, by Richard Feynman. The answer is basically that the photon doesn't bounce off of anything! It "interacts" with an electron, and another photon is emitted. Why is it emitted at the particular angle? That's what the book is all about. Way too much to explain here. But if you want to understand in layman's terms how reflection and refraction work, and why glass is transparent, get that book, it's wonderful.
      • I read that as "[looks around for mod points and finds nose]" which is far, far funnier. And they're bombarding the photon beam with electrons, not photons. Similar questions still apply.

  • FLASH! Ahhhhh (Score:3, Funny)

    by Anonymous Coward on Friday June 20 2008, @01:09PM (#23876273)

    Savior of the universe!

  • I have a flashlight that will shoot a beam out in 1 nottasecond. Also, imagine the stop-motion sports photos you could get with 80-attosecond film speed!

    • Forget sports...
      how about those "Khaaaaaaaaaaaaaan!" moments in the movies?

      Hours and hours enjoyment!

  • Ummm.. (Score:5, Funny)

    by InlawBiker (1124825) on Friday June 20 2008, @01:30PM (#23876581)

    I hate to be a pedantic killjoy, but on that film the light flash lasted about 3 seconds. I could see it pretty well with my naked eye.

    Try again, science!

  • Electron movement? (Score:3, Funny)

    by Thelasko (1196535) on Friday June 20 2008, @01:32PM (#23876617) Journal

    Jonathan Marangos at Imperial College London, UK, says the super-short flashes could let researchers image the movement of electrons around large atoms.
    So, you take a picture of it. Now you know where it is. But how fast is it going?

    Does anybody else see the problem here?

  • I am SO going to use this in a speech about my cousin's wedding night when we throw his stag next week. "Fast, you say? I'll tell you about fast..."

  • ... it'll still take Wallgreens an hour to develop the film.

      • Re: (Score:3, Interesting)

        by mikael (484)

        Look at ocean waves travelling along the coast line. While a wave can be said to have energy through the momentum of water, there is no actual wave particle itself, just the interaction of all the water molecules interacting together, along with gravity to keep everything together.

    • They're effectively the same thing. If no light falls on your detector, it's essentially the same as having a closed shutter. When you can figure out how to open and close a shutter in less than a trillionth of a second you can let them know. It's far easier to create a short pulse of light.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      No, shutters are used to limit the ambient light from reaching the film (or sensor). In a situation like this you are limiting the light being produced. So no shutter is needed - just leave the film exposed for the whole experement, when the light is produced it will be recorded (you record the rest of it too, but it records as nothing).

    • Isn't shutter speed the problem?

      They set their camera to the B (bulb) setting which keeps the lens open as long as the button is depressed. Set your camera to where you want to take a picture, screw a cable release into the shutter release button of a camera, turn off all lights in the room, depress cable release button and tighten the screw to keep the shutter open, trigger your action and the flash to capture the action, loosen the cable release so the shutter now closes, turn on lights in room. Ri

      • Re:What about shutter speed? (Score:5, Informative)

        by egomaniac (105476) on Friday June 20 2008, @01:53PM (#23876943) Homepage

        Consider a 35mm film camera with a mechanical shutter... what degree of force and mechanism would be required to move that shutter to open AND close the height of 24mm in 80 attoseconds? IANAPhysicist, but I doubt human hands could hang on to it.

        Apparently we're not realizing just how short 80 attoseconds is. You doubt human hands could hang on to it? Moving 24mm in 80 attoseconds is faster than the speed of light. Not only is it faster than the speed of light, it's a million times faster than the speed of light.

        Light only travels 24 nanometers in 80 attoseconds. [google.com]

          • Re:What about shutter speed? (Score:5, Informative)

            by kjots (64798) * on Friday June 20 2008, @05:40PM (#23880215)

            Your safe search is off, which triggers my URL filtering to block google. It's a great way to catch people who hang out on the seedier side of google images.

            Or people who don't like to have their search results artificially curtailed by someone else's sense of unreasonable morality.

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