Strong coupling and rabi oscillations in GaAs/AlGaAs heterostructures as a result of electron–hole pair condensation at room temperature

The experimental results of the investigation of coherent terahertz oscillations of the electromagnetic field from GaAs/AlGaAs heterostructures during the superradiant pulse generation have been presented. Optical doublets, which are typical for Rabi oscillations, with the splitting of 1.3–4.4 meV at 860–890 nm wavelengths have been discovered. The corresponding coherent oscillations in the time domain have been detected. The effect has been only observed in the strong coupling regime of the field with the electron–hole system. It has been demonstrated that it is the condensation of $e-h$ pairs in phase space that makes the strong coupling p-ossible in the present experimental conditions. The experimental result is yet another convincing evidence of the $e-h$ condensation in bulk GaAs at room temperature, which has been discussed in our previous publications.