How polarized light passes through a medium
Jun 05, 2021
Let us first understand how polarized light passes through a medium. Polarized light means that the vibration direction of light waves vibrates along one axis. The vibration of light wave is divided into electric field component and magnetic field component. Here we are only interested in its electric field component. We only need to pay attention to this electric field characteristic of light.
The vibration of polarized light is only in one direction, that is, only on one polarization plane. If this plane of polarization is injected into a medium with a slow axis and a fast axis, the plane of polarization will rotate.
We can divide the electric field component into two vectors in the direction of the fast axis and the direction of the slow axis. Due to the strong competitiveness of the fast axis and the slow axis, the plane of polarization will be rotated.
When the light wave first enters this medium, its vibration direction is -45°, and when it passes through this medium, its vibration direction rotates to +45°. When it exits this medium, its polarization plane rotates by 90°. °. Therefore, a medium with fast and slow refractive index has birefringence, which can rotate the plane of polarization.
