Kerr Effect

The Kerr effect is a birefringence created in a material by an external electric field. It was discovered in 1875 by the Scottish physicist John Kerr, and is characterized by the existence of two different refractive indices: a beam of light is divided into two beams when it penetrates this material. The physical phenomena responsible for this effect in matter may be, depending on the material, the electrostriction, photorefractive effect and molecular orientation, among others.

The created birefringence, unlike that of the Pockels effect, varies according to the square of the applied electric field. The materials generally have a very weak Kerr effect, however, some liquids have a measurable Kerr effect.

An electric field applied to a material generates a birefringence in this material: light has a different refractive index depending on whether its polarization is orthogonal or parallel to the field. The difference between these two indexes is:

& # x0394; n = & # x03BB; K E 2 & # xA0; {\displaystyle \Delta n=\lambda KE^{2}\ }

where:

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