Investigating spinterferometry

: first order coherence of charged quantum dots

Abstract

In recent years, quantum technologies have become a rich area of research and development. Semiconductor platforms, namely quantum dots, have been proposed as a potential solution to applications including quantum computing, quantum memory, and single photon sources. In this thesis, we examine the coherence properties of the electron in a charged InGaAs quantum dot sample within a photonic micropillar cavity. We take advantage of the deterministic light-matter interaction between photons and the electron in the quantum dot in order to probe spin dynamics and coherence properties by interfering photons that have scattered off of the two-level system, and we examine the visibility of the resulting interference fringes. We will show how significant background noise from the probing laser may convolute visibility measurements to the extent that the expected profile from the quantum dot changes. Furthermore, we will examine phonon interactions as one of the dominant dephasing mechanisms that arises in these systems, as well as investigate how the spin state can be manipulated with ultrafast laser pulses with a specific polarization. Long coherence times and control of the quantum state are imperative for maintaining stable superposition states, entanglement, and performing quantum logic gates, required for quantum computing.

Date of Award	26 Nov 2020
Original language	English
Awarding Institution	The University of Bristol
Supervisor	Ruth Oulton (Supervisor) & Edmund G H Harbord (Supervisor)