Question

Define polarisation by reflection

Answer 1

If light strikes an interface so that there is a 90o angle between the reflected and refracted rays, the reflected light will be linearly polarized. The direction of polarization (the way the electric field vectors point)is parallel to the plane of the interface.

The special angle of incidence that produces a 90o angle between the reflected and refracted ray is called the Brewster angle, qp.

Answer 2

Reflecting light on a specific non-metallic surface, at a particular angle of incidence will polarise light. Light that is reflected on the specific non-metallic surface and crossing the interface will cause the atoms to absorb the light temporarily and electrons to vibrate in the direction of electric field of the light ray. It gets re-emitted with an electric field vector, perpendicular to direction of the propagated waves. This is termed Polarisation by reflection.