Quantum-bit rotations in single quantum dots: Rabi oscillations of excitons and biexcitons

Summary form only given. We use transient nonlinear optical spectroscopy to demonstrate Rabi oscillations between each of the dipole coupled states, corresponding to qubit rotations. The interface fluctuation GaAs quantum dots are probed with sub-micron spatial resolution. The resonant excitation of the biexciton requires a two-color scheme in a hyper Raman gain configuration. To demonstrate exciton Rabi oscillations, the laser wavelength is fixed at the exciton resonance. Exciton and biexciton Rabi oscillations correspond to qubit rotations of the |00> to |01> or |10> state and the |01> or |10> to |11> state respectively, depending on the polarization of the excitation field.