Home >> Science & Nature >> Science

Explanation of the Polarization of Light

Although polarized light may seem far removed from everyday life, it plays a role in everyday products like glasses and household windows. At theme parks, for example, some rides use three-dimensional projections, requiring the audience to use special glasses. These glasses use uniquely polarized lenses that allow users' left and right eyes to receive different images. Some sunglasses also work as a filter for polarized light, reducing the amount of sunlight that reaches the wearer's eyes.

Light as an Electromagnetic Wave
- Light travels in the form of an electromagnetic wave. An electromagnetic wave is made up of perpendicular electric and magnetic fields that continually fluctuate up and down, side to side or any angle in between. The rate at which these fields fluctuate determines the color of the light. If these fields fluctuate fast enough, the wave is no longer in the range of light visible by the human eye. Likewise, if the wave fluctuates too slowly, it may drop below the capabilities of human vision.
Linear Polarization
- Normally, an electromagnetic wave fluctuates at many angles, up and down, side to side, and anything in between. Linear polarization occurs when these electromagnetic waves are forced to fluctuate at only one angle. For example, a light undergoes linear polarization when its electromagnetic waves only fluctuate from side to side.
Polarizer
- A polarizer is a material that allows light at only one specific angle of fluctuation to pass through. For example, if a lens on a pair of sunglasses is considered a polarizer, that lens may only allow light whose waves fluctuate up and down to pass through.
Easy Axis
- The easy axis is the angle at which a polarizer allows light to pass through. For example, a pair of glasses that has a horizontal easy axis only allows electromagnetic waves that fluctuate from side to side pass through. To experiment with polarizers and the easy axis, view a light source through two different polarizers. If you rotate one of the polarizers while holding the other steady, you will notice a change in the level of light allowed to pass through. Most polarizers have a horizontal or vertical easy axis. When two easy axes are parallel, light passes through normally. When two easy axes are held perpendicular, no light passes through.

Science