  Optical control of the lateral quantum confinement and number of electrons
confined in nanofabricated GaAs/AlGaAs quantum dots is achieved by illumination
with a weak laser beam that is absorbed in the AlGaAs barrier. Precise tuning
of energy-level structure and electron population is demonstrated by monitoring
the low-lying transitions of the electrons from the lowest quantum-dot energy
shells by resonant inelastic light scattering. These findings open the way to
the manipulation of single electrons in these quantum dots without the need of
external metallic gates.
