Scattering of Electromagnetic Radiation by a Nonequilibrium Electron-Phonon System

The scattering of electromagnetic radiation from an electron-phonon system not in thermal equilibrium has been studied. In particular, an enhancement of the cross section at the phonon line is found when the electrons are forced to drift relative to the ions. For some semiconductors for which the phonon frequency is approximately equal to the plasma frequency, such a scattering experiment would provide information on the phonon line and the plasma line simultaneously.