Page 68 - Sphurana 2020-21 (4)

Methods Used in the Polarization of Light

There are a few methods used in the polarization of light:

➢ Polarization by Transmission
➢ Polarization by Reflection

➢ Polarization by Scattering
➢ Polarization by Refraction

The most common method of polarization involves the use of a Polaroid filter. A
polaroid is a device used to produce plane polarised light. In 1934 E.H Land invented

a method of aligning small crystals to obtain large polarising sheets. These sheets are
called Polaroid sheets.

These sheets contain long-chain molecules that are aligned to allow electric field

oscillations along only one direction. when a beam of unpolarised light is incident on
a polaroid film, the vibrations parallel to the long chain of polymer molecules are
completely transmitted where as the vibrations in the perpendicular directions are

absorbed. Thus, beam coming out of a polaroid is plane polarised.

Uses of Polaroids

Following are the applications of polarization:

➢ Polaroids are used to see the three-dimensional pictures.
➢ They are used in laboratories to produce plane polarised light and analyse

light.
➢ They are used in head lights and wind shields of automobiles to reduce the
glare.
➢ Polaroids are used is used in sunglasses to reduce the glare.

➢ They are used to increase the colour contrast in old paintings.

Shwetha TP
(Lecturer in Physics)

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