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What is the Faraday Effect?
The Faraday effect is a magneto-optic phenomenon in which the polarization state of light rotates as it propagates through a material subjected to a magnetic field. The rotation depends on the magnetic field strength, the material, and the length of the optical path.
The Faraday effect is particularly important in fiber-optic current sensing, optical isolators, and magneto-optic devices, where it enables optical measurement or control based on magnetic fields.
HOW the Faraday Effect Works
The Faraday effect occurs when a magnetic field changes the propagation of the two circular polarization components of light differently, resulting in a rotation of the polarization plane. Unlike ordinary optical activity, the direction of Faraday rotation is determined by the direction of light propagation relative to the magnetic field.
Magnetic field applied
Light propagates through a magneto-optic material while a magnetic field is present along the direction of propagation.
Different propagation
The magnetic field causes the two circular polarization components to experience different refractive indices.
Polarization rotation
When the components recombine, their phase difference produces a rotation of the light's polarization. The rotation increases with magnetic field strength and interaction length.
