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Light Pulse Travelling Through A Water Bottle (trillion frames per second)

  1. Dec 13, 2011 #1
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Dec 14, 2011 #2


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    FYI. I have a thread in Fun Photos and Games that is all about high speed slow motion photography here.

  4. Dec 14, 2011 #3
    Someone commented on that video:

    'They should perform the double slit experiment . . ' with this setup.

    It would be neat to see..
  5. Dec 14, 2011 #4


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    Background on the technology that created your video.

    For instance for ultrasound, this can be replaced with this technology
    which analyzes how light scatters volumetric-ally within the human body.

    Last edited by a moderator: Sep 25, 2014
  6. Dec 14, 2011 #5


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    Dang you Kevin, you had me going there for a bit.

    It's a strobe system. It's the repeated nature of the signal and the repeated photo captures with slightly different delays that makes the final video.

    Lordy. :tongue2:
    Last edited by a moderator: Sep 25, 2014
  7. Dec 14, 2011 #6


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    Those MIT guys are if nothing else a clever lot, eh ??!!

  8. Dec 14, 2011 #7
    If you observe the light going through the slits, you don't get the interference pattern.
  9. Dec 14, 2011 #8

    Chi Meson

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    I read through some of the comments and I learned that photons are luxons, unlike other things made of bradyons, and electrons are made of quarks.

    I'm dummer now.

    I'm gonna buy a Hummer.
  10. Dec 14, 2011 #9
    i'm guessing you don't even know what a luxon is.

  11. Dec 14, 2011 #10

    Ivan Seeking

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    I think I can see a neutrino just ahead of the light pulse.
  12. Dec 14, 2011 #11
    A luxon is a particle with an imaginary rest mass

    A bradyon has a rest mass greater than zero

    A photon is neither a luxon nor a bradyon since its rest mass is equal to zero.

    Electrons are elementary particle and as are quarks, both of these are bradyons.
  13. Dec 15, 2011 #12
    Right, but remember this is a series of 1 dimensional videos laid together. In the runs of the experiment where the video wasn't trained on a slit the wave function wouldn't collapse? I mean, does the wave collapse when you constrain the particles position slightly or fully? I guess I don't really know everything about the experiment, now that I think about it. :D

    Someone is probably dummer for my comments, probably just me though.
  14. Dec 15, 2011 #13
    If a photon pulse was coming through both slits would you see two photon pulses with half the intensity of the original pulse?

    Any strobe based delay system like this would be expected to record and accumulate anything that had a realistic probability of occurring. The only way you would really see any measureable difference would be if you could reduce the pulse size down to a single photon. It would be difficult to do with this setup if the pulse is exciting gas that is picked up by the strobe.

    If you could get down to a level where you could tell the difference between the output of even and odd numbers of photons in the pulse beam you would probably see some interesting things. With just three photons would you expect a 50:50 split or 33:66 or 66:33?
  15. Dec 15, 2011 #14

    Chi Meson

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    I have to admit I never heard of a "bradyon" before, and I thought the poster was corrupting "baryon." :redface:

    Though I'm pretty sure that you won't find a quark inside an electron.

    And the Hummer was a stupid idea.

    Still the lesson remains: don't read comments under Youtube videos.
  16. Dec 15, 2011 #15
    If you observe the photons at the slits, you will see a 2:1 ratio and no interference pattern at the screen. If you don't observe the photons at the slits, you will see an interference pattern at the screen and be able to infer a 1:1 ratio from the pattern.

    What feathermoon suggests is that we observe the photons at the slits and record it. Then observe the photons at the screen and record that. Then photoshop the two recordings together. I think that it would work.
  17. Dec 15, 2011 #16
    Yea, just it being a 1 dimensional recording makes me wonder. Is there an experiment where only part of the slit is looked at? Would there be no interference pattern or a partial pattern? Does constraining a particle to a smaller area completely collapse its wave function or partially collapse it?
  18. Dec 15, 2011 #17
    All theory aside, I just thought it was a cool video. Kinda like a photon torpedo....
  19. Dec 16, 2011 #18
    It's a one dimensional recording because all of a second dimension is projected onto the one dimension. I don't see how you could set it up so that only part of that second dimension was projected. What did you have in mind?
  20. Dec 16, 2011 #19
    Hi Jimmy,

    In the context of the pulse and the strobe setup you would capture both before and after with different pulses and the screen itself would be unnecessary.
  21. Dec 16, 2011 #20
    Before and after what? Before the photons reach the slits, nothing interesting happens. If you observe them after they pass the slits, but before they reach the screen you destroy the inteference pattern. The only way I can see to make this work is to film it twice, once at the slit and once at the screen. Then combine the two sequences to make it look like they were one.

    Edit: I take it back. This would not work. As soon as the photons leave the slit, the interference pattern is already broken. Having once seen the photons past the slit, the interference pattern is ruined and cannot be reassembled somehow at the screen end. In other words, once you see planes departing, some for New York, some for Los Angeles, there is no way to have some of them arrive in St. Louis unless you bend their paths. Once you observe them at the slit, the inteference pattern is already ruined.
    Last edited: Dec 16, 2011
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