Reflection from a fluid in a uniform electric field

A fluid polarized by an electrostatic field E may exhibit reflection effects linear in E that cannot be observed in either transmission or light scattering. Fresnel reflection amplitudes are derived by means of a multipole theory, to the order of electric quadrupoles and magnetic dipoles, for light incident at a vacuum—fluid interface when the applied field E is either normal to the boundary or parallel to it. These Fresnel amplitudes are expressed in terms of the angle of incidence and the properties of the fluid which are induced both by the electrostatic field and the light wave fields. Experiments based on the differential reflection of orthogonal polarizations of the incident light beam are described for measuring the induced property linear in E for a fluid.