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Optical computers and the speed of light

  1. Nov 14, 2007 #1
    I saw an article http://www.washingtonpost.com/wp-dyn/content/article/2007/01/18/AR2007011801683.html which is talking about how creating a device that slows down light would be necessary to make optical computers.

    My question is is there already a way to slow down electricity because according to the article this is what transistors do.

    If this is true would it be possible to use some kind of electrical device to slow down a television signal by say 5 minutes, so that you could have two antennas one which was normal and one which was slowed down by 5 minutes, and then you could watch every channel just like with a regular TV except it would all be 5 minutes behind.
  2. jcsd
  3. Nov 14, 2007 #2


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    Note that is says "halt", not "slow down". i.e. they are simply talking about transistor based memories.
    There is no need to "slow down" the signal in the antenna (it can be done using a delay line, although a 5 min delay line would be VERY long); it is much better to use a RAM chip or a harddrive. Set-top boxes with HDs (e.g. Tivo) have been around for many years and they can do exactly what you are asking about.

    The problem with optical computers is that there is no way to "halt" light for long periods of time, i.e. no one has been able to figure out how to build an "optical memory".
  4. Nov 14, 2007 #3

    Claude Bile

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    All-optical buffers are currently a HUGE headache for people working in this field, as yet no one has come close to designing something remotely feasible.

    People have been able to make optical memory, however it is of the read-only variety, I believe researchers are tinkering with the idea of erasable holographic memory to create optical RAM.

  5. Nov 16, 2007 #4
    So how do normal computers buffer?
  6. Nov 16, 2007 #5


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    Memory is basically storing a small amount of charge on a capcitor.
    Because of the high resistance it stays there.
    You can use it to switch a transistor on/off to read it
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