Abstract
The properties of localised dipole emitters in the form of a quantum dot or a colour centre embedded in a crystal environment can be drastically modified by a change in the composition, size and shape of the environment in which the emitter is embedded. Thanks to recent advances in material deposition techniques and lithography, as well as the advances in detection techniques and optical manipulation, experimental work is now capable of revealing a new range of physical phenomena when the typical dimensions are of the order of an optical dipole transition wavelength and below. These advances have arisen at a time of a heightened research effort devoted to the important goal of identifying a qubit and a suitable environment that forms the basis for a scalable hardware architecture for the practical realisation of quantum information processing. A physical system that we have recently put forward as a candidate for such a purpose involves localised emitters in the form of quantum dots or colour centres embedded in a nanocrystal. This suggestion became more persuasive following the success of experiments which, for the first time, were able to demonstrate quantum cryptography using a nitrogen vacancy in a diamond nanocrystal as a single-photon source. It has, however, been realised that a more versatile scenario could be achieved by making use of the interplay between dielectric cavity confinement and dipole orientation. Besides position dependence the main properties exhibit strong dipole orientational dependece suggesting that the system is a possible candidate as a qubit for a scalable hardward architecture for quantum information processing. Cavity confinement can control processes since it can lead to the enhancement and the complete suppression of the de-excitation process, with further control provided by the manipulation of the dipole orientation by optical means. This article is concerned with the modelling of quantum processes for quantum systems localised in artificially fabricated structures made of high conductivity metals and dielectric cavities. The essential features of cavity field confinement in this context are presented and the effects on de-excitation rates are assessed.