Ultrafast spectral hole burning spectroscopy of exciton spin flip processes in InAs/GaAs quantum dots

摘要

The exciton spin relaxation within the radiative doublet of the exciton ground state in InAs/GaAs self-assembled quantum dots is studied via an ultrafast spectral hole burning technique. In the case of cross-polarized pump and probe pulses a spectral "antihole" emerges due to relaxation of the - exciton spin. The measured relaxation time decreases rapidly from 1.15 ns at T = 5 K to 90 ps at 90 K, suggesting exciton-acoustic phonon interaction as the underlying spin relaxation mechanism.