Polarization of electromagnetic waves refers to the geometrical orientation of their oscillations.
Polarization restricts the orientation of the oscillations of the electric field of electromagnetic waves to a single plane from the point of view of an observer. This phenomenon is known as plane polarization.
- Plane polarization filters out all the waves where the electric field is not orientated with the plane from the point of view of an observer.
- To visualize plane polarization, imagine trying to push a large sheet of card through a window fitted with close-fitting vertical bars.
- Only by aligning the card with the slots between the bars can it pass through. Align the card at any other angle and its path is blocked.
- Now substitute the alignment of the electric field of an electromagnetic wave for the sheet of card, and plane polarization for the bars on the window.
- Polarizing lenses used in sunglasses rely on plane polarization. The polarizing plane is orientated horizontally and cuts out glare by blocking vertically aligned waves.
- Plane polarization is one of the optical effects that account for the appearance of rainbows.
- It is the position of each raindrop on the arc of a rainbow, with respect to the observer, that determines the angle of the polarizing plane.
- Rainbows are typically 96% polarized.