Population inversion and IR emission under real space transfer: prospect for a new source

New mechanism for population inversion between continuum and shallow bound state in QW of the selectively doped MQW systems under real space transfer in the high lateral electric field is put forward. First observation of FIR and mid IR emissions on continuum-to-bound and bound-to-bound transition and absorption of FIR radiation in selectively-doped InGaAs-GaAs MQW systems under the transfer are presented.