Resonant interaction between a quantum dot and a narrowband laser: spectroscopy and optical pumping of a single spin

Recently, a technique has been developed for performing laser spectroscopy on single self-assembled quantum dots. A summary is presented here of spectroscopy results concerning the charge- and magnetic-field dependent energies and selection rules of the fundamental exciton. In addition, it is also shown how the resonant interaction of a laser with a singly-charged dot can be exploited to pump the electron into one of the spin states. This involves applying a small magnetic field and an appropriate bias in order to suppress spin relaxation through the hyperfine interaction and through co-tunneling processes, respectively.