Radiation pressure and momentum transfer in dielectrics: The photon drag effect

Abstract

The momentum transfer from light to a dielectric material in the photon drag effect is calculated by evaluation of the relevant Lorentz force. In accordance with measurements on Si and Ge, the material is taken as a two-component optical system, with charge carriers described by an extinction coefficient $\ensuremath{\kappa}$ in a host semiconductor described by real refractive indices ${\ensuremath{\eta}}_{p}$ (phase) and ${\ensuremath{\eta}}_{g}$ (group). The calculated momentum transfer to the charge carriers alone has the value ${\ensuremath{\eta}}_{p}\ensuremath{\hbar}\ensuremath{\omega}∕c$ per photon, the so-called Minkowski value, found experimentally. The time-dependent Lorentz force is calculated for light in the form of a narrow-band single-photon pulse. When the pulse is much shorter than the attenuation length, which is much shorter than the sample thickness, there is a clear separation in time between surface and bulk contributions to the forces. The total bulk momentum transfer (charges plus host) in this case is found to be $\ensuremath{\hbar}\ensuremath{\omega}∕{\ensuremath{\eta}}_{g}c$, the so-called Abraham value.