what is polarisation? What are the types of polarisations?

Answer 1

Polarization is the orientation of the electric field of light. Since light is a "transverse" wave, the polarization axis is perpendicular to the direction the light is traveling. There are many types of polarizations:

Linear polarization
Circular polarization (right or left handed)
Elliptical polarization
Unpolarized


Linearly polarized light is where the electric field oscillates back and forth along a single direction, for example vertical, horizontal, or at any other single angle which is perpendicular to the direction the light is traveling.

Circularly polarized light is where the electric field direction for each wavelength of light in the beam rotates all the way around once per wavelength or cycle at a constant magnitude. Circularly polarized light can be either right-handed or left-handed. If you curl your fingers with the thumb out straight, and your thumb points in the direction the light is traveling, your fingers point in the direction the field is rotating.

Elliptical polarization as has a field direction which rotates rapidly around the direction of travel, but with non-constant magnitude as it goes around.

Unpolarized light does not have a single polarization state, but consists of multiple polarization states without a steady phase relationship.

The other answers give some common methods for how light gets to be polarized and what some of the uses are. Probably the most common use of deliberately polarized light is in liquid crystal displays.

Answer 2

Polarisation refers to the alignment of a ray of light. Light consists of an oscillating magnetic and electric vector point perpendicular to the direction light is travelling and perpendicualr to each other. A light beam will consist of many light particles or photons, each of which maybe rotated relative to each other. Thi sis teh typical case for light bulbs and then sun, which are is called unpolarized light. Certain light sources, in particular, lasers can produce light with all the photons having the same polarization, (as well as the same wavelength and phase).
There are special materails or filters that aborb light of one particular polarization, these are called polarizing filters, teh most common as seen in sunglasses absorbs light in one direction but not another. There are other special filters that absorb circularly polarised light, that is light whose polarization is clockwise as opposed to anti-clockwise. An example of this is if you place two linearly polarizing filters rotated 90' to each other before and after a material such as a car windscreen. You may expect no light to come through, but due to the birefringence of the glass you will see some interesting colors repersenting the stresses in the wind shield.

Light reflects and scatters differently depending on the parts that are polarized parallel and perpednciualr to the plane or incoming and reflected ray. The blue light in the sky can be highly polarised, photographers often use polarising filters on their lenses to increase the contrast between the sky and clouds.

Also in special birefringent crystals, light is refracted differently depending on its polarization, this leads to seeing a double image when looking through the crystal.

Answer 3

Polarisation refers to the direction of the electric vector in an electromagnetic wave. Light may be polaised by inserting a beam of unpolarised (or natural) light into a device or piece of material called a polariser, which transforms the light into polarised light.
The polariser (eg. polaroid sheet) only transmits those waves which have a component of the electric field in the direction of the polarisation direction (direction of the electric field) of the sheet.
Methods of polarisation include:
- polarisation by absorption
- polarisation by reflection
- polarisation by birefringence
- polarisation by scattering

Answer 4

its something.