Book Description

Cavity quantum electrodynamics has enabled unprecedented control over the fundamental interaction of light and matter. New types of on-chip optical technologies that exploit the quantum mechanical nature of light have the potential to open up an entirely new direction for semiconductor devices, combining the fine control of cavity quantum electrodynamics with the convenience of the semiconductor platform. However, the practical implementation of quantum technologies on a chip will require an on-demand source of non-classical states of light, such as pulses with a well-defined number of photons. In this dissertation, I present the development of a semiconductor non-classical light source based on coupling artificial atoms (quantum dots) to small mode-volume optical resonators (photonic crystal nanocavities). The strong coupling we achieve between a quantum dot and a photonic crystal nanocavity produces a hybridization of the quantum dot excitation with the optical field confined inside the cavity. I demonstrate how the rich energy structure exhibited by this system enables us to control the statistics of photons in a transmitted laser beam, moving between sub-Poissonian and super-Poissonian on demand. I also discuss how these non-classical states of light can be characterized by examining the higher-order photon correlations measured via a generalized Hanbury Brown and Twiss type interferometer. Furthermore, I show that by detuning the quantum dot resonance away from the cavity resonance, we can improve both the purity and the efficiency of single-photon generation in this system. This approach allows us to combine the high fidelity of single quantum emitters with the high repetition rate and accessibility of optical cavities. Finally, I explore methods for scaling up this system by fabricating multiple photonic crystal nanocavities in such a way that they couple to each other. I present the experimental realization of a photonic molecule (two coupled photonic crystal nanocavities) that is strongly coupled to a quantum dot contained inside one of the component cavities. I also examine the fabrication of coupled optical cavity arrays in this photonic crystal platform. Our experimental findings demonstrate that the coupling between the cavities is significantly larger than the fabrication-induced disorder in the cavity frequencies. Satisfying this condition is necessary for using such cavity arrays to generate strongly correlated photons, which could potentially be used for the quantum simulation of many-body systems.