Amplification of interface phonons in quantum well systems in two laser fields

Abstract

Amplification of interface optical phonons in quantum well systems in the presence of two laser fields, namely a weak laser field and an intense laser field, is reported here. The rate of change of the phonon population due to the scattering of the free quasi-two-dimensional electrons in the presence of the two laser fields is calculated from which the amplification coefficient is derived. It was found that interface optical phonons propagating parallel to the direction of polarization of the two radiation fields may become unstable over a relatively wide band of phonon wavenumbers. An a p plication is made for a nondegenerate semiconductor GaAs/AlAs quantum well system.