AMPLIFICATION OF INTERFACE PHONONS IN QUANTUM-WELL SYSTEMS IN 2 LASERFIELDS

Amplification of interface optical phonons in quantum well systems in the presence of two laser fields, namely a weak laser field and an int ense laser field, is reported here. The rate of change of the phonon p opulation due to the scattering of the free quasi-two-dimensional elec trons 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 wid e band of phonon wavenumbers. An application is made for a nondegenera te semiconductor GaAs/AlAs quantum well system.