Pulse Optical Driving of Cavity-Coupled Open Quantum Systems

Cavity coupled solid-state systems have shown great promise for the physical realisation of scalable, on-chip optical quantum technologies. Using ultra-fast optical pulses the states of such systems can be manipulated on extremely short timescales. However, while these quantum systems have demonstrated atomic-like properties, strong interactions with the solid-state environment introduce additional processes not found in purely atomic systems. This thesis considers the control of open quantum systems (namely Quantum Dots (QDs)) through pulsed optical driving, and the impact of coupling to the environment.

While the effects of this environmental coupling on the emission properties (g^{(1)}(t) and g^{(2)}(t)) of QDs are well-known under Continuous Wave (CW) driving, there has been relatively little work studying these properties in the pulsed driving regime.
Using the polaron formalism we show the asymmetry in the emission spectra under CW driving is enhanced under pulsed optical driving, in addition to the Mollow satellite peaks that appear in the spectrum in this limit. Furthermore, by extending the variational polaron model to include pulsed optical driving, we present a formalism describing the QD-phonon coupling that remains valid in the limits of long pulse duration and strong driving, where the traditional weak-coupling and polaron formalisms respectively break down.

Additionally, by performing full Cavity Quantum Electrodynamics (cQED) calculations, we consider how the configuration of optical cavity structures may be optimised to improve the fidelity of the initialisation and readout of single charge-carrier spins confined to semiconductor QD in a single Voigt geometry magnetic field. We show an optical cavity with a single, linearly polarised cavity mode is able to support both high-fidelity spin initialisation and readout, and always out-performs bi-modal cavities in realistic driving regimes. Moreover, we experimentally characterise a potential cavity candidate, demonstrating a flexible design with the ability to form single- or bi-modal cavities with directional cavity emission.