Excitonic Rabi oscillations in semiconductor quantum dot observed by photon echo spectroscopy.

Optical properties in single-layer InGaAlAs/GaAlAs semiconductor quantum dots were studied by two-pulse photon echo technique. From the decay time, the optical coherence time of the excitons was estimated to be 2.5 ns, which is independent of the excitation intensity. We also observed the excitonic Rabi oscillations by measuring the photon echo intensity as a function of the excitation pulse area. The observed oscillatory structure is not expected from two-level systems. [ABSTRACT FROM AUTHOR]