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Laser Diffraction Logic?

  1. Jul 24, 2012 #1
    I'm sure someone has tried this, and I'm sure there's a reason it's not something that is widely used, but here's a question:

    Can a logical NOR gate be created by shining two lasers (an A and B input) through tiny slits (like the double-slit experiment), and determining an output at a known distance away, based on whether or not the waves cancel out at that point?

    In other words, you line up the lasers super close together. You turn one on and shine it through a slit, it creates a certain diffraction pattern. You turn the other one on separately and shine it through another slit very nearby, and position it so that it creates the same pattern (at least, the same for a given zone, say, directly in front of the slit). But you position them so that, when you turn both on, the pattern is different. When both are on, the spot directly in front of the slits represents a spot where waves cancel.

    My question is this: does it work like that?
  2. jcsd
  3. Jul 25, 2012 #2


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    Staff: Mentor

    As you need a coherent source, using a single laser and a beam splitter should be better as source.
    You would get an OR at positions of positive interference and XOR at positions of negative interference.

    There are some concepts of purely light-driven logic gates (mainly for internet traffic). I think they do not use double slits, but nonlinear effects in material.
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