We have determined both the real and imaginary parts of the dielectric polarizability of a single quantum dot. The experiment is based on the observation and the manipulation of Rayleigh scattering at photon frequencies near the resonance of an optical exciton transition in single self-assembled InAs and InGaAs quantum dots. The interference between the narrow-band laser field and the weak electromagnetic field coherently scattered by the quantum dot is detected with a cryogenic Fabry-Perot setup by combined differential transmission and reflectivity measurements.
@article{arxiv.cond-mat/0509114,
title = {Absorptive and dispersive optical responses of excitons in a single quantum dot},
author = {B. Alén and A. Högele and M. Kroner and S. Seidl and K. Karrai and R. J. Warburton and A. Badolato and G. Medeiros-Ribeiro and P. M. Petroff},
journal= {arXiv preprint arXiv:cond-mat/0509114},
year = {2007}
}