Radiation pressure and the linear momentum of light in dispersive dielectric media

Abstract

We derive an exact expression for the radiation pressure of a quasi- monochromatic plane wave incident from the free space onto the flat surface of a semi-infinite dielectric medium. In order to account for the total optical momentum (incident plus reflected) that is transferred to the dielectric, the mechanical momentum acquired by the medium must be added to the rate of flow of the electromagnetic momentum (the so-called Abraham momentum) inside the dielectric. We confirm that the electromagnetic momentum travels with the group velocity of light inside the medium. The photon drag effect, in which the photons captured in a semiconductor appear to have the Minkowski momentum, is explained by analyzing a model system consisting of a thin absorptive layer embedded in a transparent dielectric.