Unipolar lasers on the structures with variable dimensionality of electronic states

We review our works aimed at the creation of a unipolar laser with the efficient suppression of nonradiative relaxation between the laser subbands owing to strongly asymmetric in height barriers surrounding an active element. The asymmetry of the barriers causes the existence of a lower laser subband only within a narrow region of in-plane momenta. In such a way one-phonon relaxation between the laser subbands can be significantly suppressed