Polarisation of light
Intermediate
Light with E field in a single plane.
Unpolarised light has random E orientations; a polariser transmits only one direction. Light can be polarised by absorption, reflection, scattering or birefringence.
Polaroid sunglasses reduce glare.
Shows light is a transverse wave.
In more detail
Light is a transverse wave, and its electric field can oscillate in a particular plane. Polarised light has a fixed orientation, while unpolarised light has random orientations.
Real-world uses
- Polarising filters reduce glare from water and roads.
- 3D cinema uses polarised light to separate images for each eye.
- Polarised light from a reflection on water reduces glare when viewed through polarised sunglasses.
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Frequently asked questions
Is sunlight polarised?
Ordinary sunlight is unpolarised, though scattered skylight is partially polarised.
Can I see polarisation?
Not directly, but polarising filters show it clearly.
How does a polariser work?
It transmits only the component of the electric field along its axis and absorbs the rest.
Related topics in Optics
Single slit diffraction · Diffraction grating · Resolving power · Malus's law · Brewster's angle · Polarisers and LCDs