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What exactly does polarization of light mean?

  1. Oct 11, 2005 #1
    What exactly does polarization of light mean?
    I researched "optically active materials" and I found that they work by rotating the polarization of light. What practical meaning does this have? Thanks!
  2. jcsd
  3. Oct 11, 2005 #2


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    It's an alteration of the plane in which the EM vibrates. Optics isn't my thing, so more detail will have to come from someone else.
  4. Oct 11, 2005 #3
    Alright, thanks. That's a start ;)
  5. Oct 11, 2005 #4

    Claude Bile

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    The polaristion is the direction that the electric field vector points.

    A device that rotates the polarisation of light rotates the electric field vector. For example, a faraday isolator rotates the polarisation of back-reflected light by ninety degrees, effectively turning say, vertically polarised light into horizontally polarised light, allowing the back-reflection to be blocked with a polaroid.

  6. Oct 12, 2005 #5


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    The whole polarization thingy is probably the most confusing subject in optics (at least for me). It's something that's rather very difficult to visualize, especially when you start to look at circularly and elliptically polarized light. Or how about non-polarized light that has electric fields in all directions... woah, how do you visualize that? The effects of polarized and non-polarized monochromatic or white light passing through birefringent or electro-optical materials can also get complex real quickly.

    The summary of it is as stated. Polarization talks about the direction of the electric field at any point along the travelling EM wave. Polarized light has many engineering applications, but the closest to home invention is probably your polarized pair of sunglasses. They filter horizontally polarized light completely. Cross two polarized sunglasses together and you will see total darkness.
  7. Oct 12, 2005 #6
    And then of course you can put a third pair of polarized sunglasses between them at an angle and see light :)
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