PHOTOINDUCED AMPLIFICATION OF PHONONS LOCALIZED IN A 2-DIMENSIONAL ELECTRON-GAS

This paper discusses how phonons localized within a two-dimensional electron gas are affected by the presence a strong electromagnetic wave whose electric field vector lies in the plane of the two-dimensional electron gas. A dispersion relation for the phonons is derived under the assumption that the electromagnetic wave affects the phonon subsystem only via the two-dimensional electron gas. When the energy of an electromagnetic wave quantum is large compared to the electron energies, new regimes of electron-phonon interaction become possible (which are forbidden by conservation laws in the absence of the wave), including regimes in which the ''attenuation'' of the phonons is negative (photoinduced gain). (C) 1995 American Institute of Physics.