Ability to Increase a Weak Electromagnetic Wave by Confined Electrons in Quantum Wells in the Presence of Laser Radiation

The analytic expressions for the absorption coefficient (ACF) of a weak electromagnetic wave (EMW) caused by confined electrons in the presence of laser radiation in quantum wells are obtained by using the quantum kinetic equation for electrons in the case of electronoptical phonon scattering. The dependence of the ACF of a weak EMW on the intensity Eot and frequency Omega(1) of the external laser radiation; the intensity E-02 and frequency Omega(2) of the weak EMW; the temperature T of the system and the width L of quantum well are analyzed. The results are numerically calculated, plotted, and discussed for AlAs/GaAs/AlAs quantum well. The numerical results show that ACF of a weak EMW in a quantum well can get negative values. So, by the presence of laser radiation, in some conditions, the weak EMW is increased. This is different from the case of the absence of laser radiation.