Electro–optic effect
An electro–optic effect is a change in the optical properties of a material in response to an electric field that varies slowly compared with the frequency of light. The term encompasses a number of distinct phenomena, which can be subdivided into a) change of the absorption Electroabsorption: general change of the absorption constants Franz–Keldysh effect: change in the absorption shown in some bulk semiconductors Quantum-confined Stark effect: change in the absorption in some semiconductor quantum wells Electrochromic effect: creation of an absorption band at some wavelengths, which gives rise to a change in colour b) change of the refractive index and permittivity Pockels effect (or linear electro-optic effect): change in the refractive index linearly proportional to the electric field.