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Who said the double-slits had to be simply slits? - applications of QM in storage

  1. Jan 21, 2007 #1


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    These guys are storing whole images using a single photon!


    I didn't think too much of the article until I read how they're doing it. It is pretty much living, breathing proof of QM's basic, weirdest principle.

    "To produce the UR image, Howell simply shone a beam of light through a stencil with the U and R etched out. Anyone who has made shadow puppets knows how this works, but Howell turned down the light so much that a single photon was all that passed through the stencil.

    Quantum mechanics dictates some strange things at that scale, so that bit of light could be thought of as both a particle and a wave. As a wave, it passed through all parts of the stencil at once, carrying the "shadow" of the UR with it. "
    Last edited: Jan 21, 2007
  2. jcsd
  3. Jan 21, 2007 #2
    How do they get so much info back out? Do they pass the single photon through a gain medium afterwards?
  4. Jan 22, 2007 #3
    That wouldn't make sense, since a gain medium can only amplify information, I don't think it can actually write info in...

    Anyway, even though I read about the double slit experiment, I don't fully understand it, so I'll leave this to the experts :)
  5. Jan 22, 2007 #4

    Hans de Vries

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    The image is not retrieved from a single photon. The picture is made up of
    many photons gathered by a scanning single photon detector.

    The proof that the image information was available in the wave-function of
    the photon comes from a separate high intensity beam experiment which
    shows clearly visible interference.

    The point they make is that they can slow down the propagation to 1/300th
    of the speed of light while retaining both phase and amplitude information.
    Here is a description of the experiment on the web page of the authors:


    Regards, Hans
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