GaAs quantum box cascade lasers

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Abstract
Measurements of the light emission under strong magnetic field from quantum cascade lasers emitting at 9 and 11 μm are reported. The laser intensity shows strong oscillations as a function of the magnetic field. This effect is due to changes in the lifetime of the upper state of the laser transition, which is controlled by electron-optical phononscattering. This process is strongly modified by the extra confinement imposed by a magnetic field applied perpendicular to the plane of the layers, which breaks the electron dispersion into discrete Landau levels. The experimental results are in remarkable agreement with our calculations of the phonon-limited lifetime. We also show that this experiment provides direct indications of the ratio of the scattering rates associated with the two nonradiative transitions in the active region.