Ultrafast Dynamics of Single Quantum Dots

In this thesis the results of experiments on the optical properties of single InGaAs quantum dots are presented. Using a range of ultrafast spectroscopy techniques the dynamics of single charge carriers confined within these quantum dots are probed. Both the coherent and incoherent driving regimes are explored with a view to applications
for quantum information processing. Three key results are described in detail in this thesis. Firstly, by performing resonant coherent driving it is shown that reduction of the quantum dot neutral exciton fine-structure splitting enables fast and high-fidelity initialization of
long-lived hole spin quantum bits. Secondly, by detuning the laser from the ground state - neutral exciton transition it is possible to both excite and de-excite exciton population through incoherent driving
via the acoustic phonon bath. Finally, by considering quantum dots coupled to optical microcavities it is shown that the driving strength of both resonant coherent and quasi-resonant phonon-assisted excitation may be strongly modulated.