An (AlGaAs/GaAs/AlGaAs)60 resonant Bragg structure based on the second quantum-confinement level of heavy-hole excitons in quantum wells

Photoluminescence and optical-reflection spectra of a periodic structure consisting of 60 tunneling-isolated GaAs quantum wells separated by AlGaAs barriers are studied. The structure is designed so that, for a certain angle of incidence (∼23o), the Bragg resonance condition is satisfied for light with a photon energy equal to the energy of heavy-hole excitons at the second quantum-confinement level in the wells. It is established experimentally that, under the conditions of double exciton-polariton and Bragg resonance, a superradiant optical mode is formed. Dependences of Bragg and exciton-polariton reflection on the angle of incidence and polarization of light and the temperature are investigated.