Nanoscale Magnetic Resonance Spectroscopy Using Individual Spin Qubits

Abstract

Nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) are essential tools for both the physical and life sciences, but have been limited to the detection of large ensembles of spins due to their low sensitivity and the macroscopic nature of the sensors. Over the past several decades, significant efforts have been directed toward pushing this sensitivity to its ultimate physical limit, the detection of individual electronic and nuclear spin signals localized in a small volume. Our approach to nanoscale sensing achieves this goal by utilizing spin qubit sensors associated with individual nitrogen vacancy (NV) color centers in diamond. In this thesis we develop new techniques and applications of nanoscale magnetic resonance spectroscopy. We begin with a brief review of several relevant properties of the NV center. In particular we discuss its level structure, the manipulation of its spin state via application of control fields and the various interactions with the local environment that lead to decoherence and relaxation of its spin state. We discuss the use of NV centers as nanoscale magnetic sensors and present a demonstration of the first magnetic resonance detection and spectroscopy of individual proteins using an approach based on quantum logic. We then demonstrate the use of NV-based nuclear quadrupole resonance (NQR) spectroscopy to probe the structure and spin dynamics of a two-dimensional material. This is followed by the first experimental realization of all-optical detection of a single electronic spin. Finally, we end this thesis with the first demonstration of the detection of a single nuclear spin at room temperature using a technique based on utilizing a network of electronic spin-1/2 qubit sensors on the diamond surface.