Wire grid polarizers

  1. I've read about wire-grid polarizers from wikipedia. The article says that waves perpendicular to the wires cannot induce electron movement and hence they pass through with minimal energy loss. On the other hand, waves parallel to the wires are reflected by the wires because electron movement is possible. What I don't understand is two things:

    1. why the electron movement doesn't also induce a transmitted wave?

    2. why must the wires need to have a separation less than the wavelength?

    Thanks
     
  2. jcsd
  3. mfb

    Staff: Mentor

    >> 1. why the electron movement doesn't also induce a transmitted wave?
    It does, and you can interpret this as wave interfering destructively with the incoming wave, so you get a small effective signal behind the wires.

    >>2. why must the wires need to have a separation less than the wavelength?
    In order to get this interference everywhere. If you have a gap inside, you cannot have this destructive interference there and waves can come through your grid.

    This is just a model - a simulation of the wires and the near field around them would give better approximations.
     
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