The basic understanding behind the MOKE is how the magnetized surface works and how it could result in a change in polarization as well as the intensity of light because of its effects. Now consider through the lens of the Faraday Effect, it could be said the MOKE is like it. The Faraday Effect for instance describes the forms of changes that could occur when light is being transmitted through a surface that is magnetic. When in the magnetic effect, the said material will be transmitted through the magnetic material and the Faraday Effect attempts to present these. On the other hand, the Kerr effect in MOKE attempted to present how the light changes occur as reflected from a magnetic surface.
Kerr effect is called the quadratic electro-optic effect. The Kerr effect is the theory where the refractive indices in material changes of phenomenon in response to an electric or magnetic field is observed. It is more prominent in some materials and is less prominent in others. There are two varying forms of the Kerr effect which are the electro optic Kerr effect and then there is the optical Kerr effect. The electro optic Kerr effect is one in which a varying DC field is applied.
The MOKE as studied will consider the Kerr effect in which light itself is considered. The electro optic effect is such that the DC current is applied to the non-linear optic medium. Here perturbation occurs based on the refractive index of material. In the case of the light-based effect it so happens that the material itself could act as a wave plate. Optical Kerr is amore of a self-induced effect hence where the light creates the force field. Now in the case of the Kerr effect, there are many off diagonal components observed at this point that would induce magneto anisotropic permittivity. Permittivity is hence allowed in different directions, in the speed of light, as given by the equation.