Population inversion among electronic subbands in optically pumped semiconductor quantum wells

A theoretical study on population inversion among different electronic subbands, induced by hot-electron interactions with LO-phonons and with photons, is presented for an optically pumped AlGaAs-GaAs double quantum well structure which may behave as a three-level system to generate far-infrared laser radiations. The results obtained indicate that at a fixed pumping intensity, the population inversion among different electronic subbands can be tuned by varying electron temperature through, e.g., applying an in-plane control voltage.