Polarization

Polarization is the phenomenon in which light wave has its vibration only in a single plane.

The light waves which contain the electromagnetic fields oscillating in all possible directions are called Unpolarized light waves.

The light waves in which the vibration of wave is restricted in a particular plane is known as Polarized light.

Polaroids are the optical devices which select a part of ordinary light to oscillate only in a particular direction.

The plane containing the direction of vibration and the direction of wave propagation is called the Plane of vibration.

The plane passing through the direction of wave propagation and perpendicular to the plane of vibration is called Plane of polarization.

Polarization Methods

1. Polarization by scattering
2. Polarization by absorption
3. Polarization by reflection

Brewster's law states that, the refractive index of a medium is equal to the tangent of the polarizing angle for the given medium.

Mathematically, $\mu$=$tan{\theta }_p$

• Polarization is only shown by transverse wave.
• Malus law is only shown by polarized light.
• Unpolarized light is symmetrical whereas polarized light is assymetrical.
• Nicol prism or tourmaline crystals are used to polarize the light.
• Necked eye cannot detect polarization.
• Polarizing angle depends upon the color of incident light.
• Light from the ordinary sources are unpolarized.
• $I\propto co{s}^2\theta$, called Malus law where $\theta$is the angle between the axis of polarizer and analyzer.
• ${\theta }_p+r=90°$