Estimates of infrared intersubband emission and its angular dependence in GaAs/AlGaAs multiquantum well structures

This letter describes results of a modeling analysis of IR radiative efficiency for cascade-type quantum well emitter structures, and the angular dependence of spontaneous emission. The radiative decay rates are calculated for different IR wavelength ranges. Estimates of radiative efficiency indicate that the performance of these cascade mode devices in the long- and midwavelength infrared range can be comparable to or superior to that reported at far-infrared range. Based upon calculations of the angular dependence of IR emission, an etched surface grating structure is proposed which should lead to high effective coupling efficiencies.