Abstract

We present a detailed theoretical analysis of LO-phonon and interface roughness scattering influence on the operation of GaAs/AlGaAs quantum cascade laser in the presence of an intense external magnetic field. The lifetime of the upper state, population inversion and optical gain show strong oscillations as a function of the magnetic field. These oscillations and their magnitude are found to be a result of the combined action of the two studied mechanisms and strongly influenced by temperature. At elevated temperatures, electrons in the relevant laser states absorb/emit more LO-phonons which results in reduction in the optical gain. We show that the decrease in the optical gain is moderated by the occurrence of interface roughness scattering, which remains unchanged with increasing temperature. Incorporation of the interface roughness scattering mechanism into the model did not create new resonant peaks of the optical gain. However, it resulted in shifting the existing peaks positions and overall reduction in the optical gain.