Explanation

The isotropic materials will show birefringence under the external electric field, which will lead to the change of refractive index, and the change of refractive index is proportional to the square of the electric field strength. This effect is called Kerr effect or secondary electrophoto effect. The materials with this effect is called Kerr materials. Theoretically, all dielectric, whether solid or liquid, may exhibit Kerr effect under the action of high external electric field. The early Kerr material were organic liquids, among which nitrobenzene, m-nitrotoluene, phenylnitrile and other Kerr effects were the most obvious. Later, it was found that cubic perovskite type crystals such as barium titanate and strontium titanate had stronger Kerr effect, and were easy to use and store. Therefore, crystal Kerr materials replaced liquid Kerr materials in many applications. However, these crystalline materials have low Curie temperature, which makes it difficult to grow materials that meet the use requirements in size and quality and are expensive. Therefore, in general, the application of Kerr material as a electro-optical materials is far less common than that of Pockels materials such as lithium niobate and potassium deuterium phosphate

Classification