Intersubband and interminiband GaAs/AlGaAs quantum cascade lasers at 10 μm

We report on the realization of injection lasers based on the GaAs/AlaAs material system. Intersubband transitions in coupled quantum wells as well as intraband transitions in a finite superlattice are used to demonstrate lasing at and above 10 mu m The active material for both systems is a 30 period sequence of injectors/active regions made from GaAs/AlaAs quantum wells. By an applied electric field electrons are injected into higher states of coupled quantum wells and relax radiative to the lower subbands or minibands, respectively. The laser emission wavelength is 10 mu m for the intersubband lasers and 12.9 mu m for the laser structure having a finite superlattice as an active cell. At a heat-sink temperature of 10 K, peak optical powers of the intersubband quantum cascade lasers exceed 300 mW (interminiband: 100mW). The maximum operating temperature is 160 K (interminiband: 50 K). (C) 2000 Elsevier Science B.V. All rights reserved.