Definition
Light that is reflected from a magnetized surface can change in both polarization and reflected intensity. The effect is similar to the Faraday effect: the Faraday effect describes changes to light transmitted through a magnetic material, while the Kerr effect describes changes to light reflected from a magnetic surface. Both effects result from the off-diagonal components of the dielectric tensor . These off-diagonal components give the magneto-optic material an anisotropic permittivity, meaning that its permittivity is different in different directions. The permittivity affects the speed of light in a material:
where is the velocity of light through the material, is the material permittivity, and is the material permeability; and thus the speed of light varies depending on its orientation. This causes fluctuations in the phase of polarized incident light.
Read more about this topic: Magneto-optic Kerr Effect
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