Non-linear optics on an exciton state in a single quantum dot

We report on non-linear effects on the exciton ground state in a single quantum dot, driven by a strong resonant optical field. The resonant excitation is achieved by embedding the quantum dots in a waveguiding structure. Thus, the light–matter coupling is enhanced, allowing the observation of Rabi oscillations up to three periods. With increasing pulse area, a decrease of the exciton lifetime is observed leading to a very rapid damping of the oscillations amplitude. Resonant coherent control experiments show that the coherence time of the ground exciton state in a single quantum dot is fast, of the order of a few tens of picoseconds. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)