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 why the electron movement doesn't also induce a transmitted wave. The article claims that the wave is existent but simply canceled out with the original incident wave, but don't waves need to be absorbed to cause electron movement? Also, why must the wires need to have a separation less than the wavelength?