Far-infrared probe of size dispersion and population fluctuations in doped self-assembled quantum dots

We investigate the FIR magneto-optical transitions in doped self-assembled InAs quantum dots with a filling ranging from 1 to 6 electrons per dot. Significant changes in the line width and the dispersion of the transitions are observed as the doping level is varied, in agreement with our theoretical calculations. We show that our technique is a very effective tool to obtain informations regarding the dot size dispersion and the electron filling fluctuations.