Exciton Rabi oscillation observed in spontaneous emissions after resonant excitation

We observed Rabi oscillations of ground-state excitons in single GaAs quantum dots (QDs). We temporally resolved emissions from the ground-state excitons after exciting the same level by picosecond short pulses. To capture weak emissions from single QDs, the reflection signals of an excitation laser were reduced by applying obliquely incident geometry and crossed polarization configuration. Rabi oscillations were observed in the emissions as a function of excitation amplitude.