Influence of superradiance on near- and far-field emission patterns in GaAs/AlGaAs heterostructures

The near- and far-field emission patterns of GaAs/AlGaAs heterostructures are studied in the regimes of lasing and generation of femtosecond superradiant pulses. It is explicitly demonstrated that, unlike lasing, superradiant emission does not exhibit such phenomena as self-focusing, instability and deformation of near- and far-field emission patterns. The observed phenomena can be explained by the properties of the coherent cooperative electron — hole state, which has been found earlier.