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What is the Faraday Rotation?
Faraday rotation is the rotation of the polarization plane of light as it propagates through a material exposed to a magnetic field. It is a manifestation of the Faraday Effect and depends on the magnetic field strength, optical path length, wavelength, and magneto-optic properties of the material.
Faraday rotation enables optical measurement of magnetic fields and electrical current, making it particularly important for fiber optic current sensing and magneto-optic devices.
HOW the Faraday Rotation Works
Faraday rotation occurs because a magnetic field causes the two circular polarization components of light to propagate at different velocities through a magneto-optic material. Their resulting phase difference rotates the polarization state of the light.
Light propagation
A polarized optical signal travels through a magneto-optic material in the presence of a magnetic field.
Circular components
The input polarization can be considered as two circularly polarized components that experience different refractive indices under the magnetic field.
Polarization rotation
The phase difference accumulated between the two components produces a rotation of the resulting polarization. The rotation increases with the magnetic field and the length of the interaction.
