UC Berkeley

Nitrogen-vacancy (NV) centers are defects in diamond with unique physical properties that make them potentially useful for a number of applications. Their emission is spin-state dependent, enabling the use of optically-detected magnetic resonance (ODMR) to study their spin states. The stability of their emission and the ability to functionalize diamond surfaces make them superior biomarkers for fluorescence imaging. Finally, their atypically long spin coherence times enable their use as a quantum bit in quantum information applications. This dissertation is concerned with the fact that the spin state of the NV center can be optically polarized, or initialized. If such polarization could be used to align the nuclear spins in a sample external to the diamond and thus enhance the raw magnetic resonance signal for any sample, magnetic resonance technology such as NMR Spectroscopy and MR Imaging could be improved dramatically.

In an effort to understand if use of the NV center to improve magnetic resonance technology is possible and to determine the best strategy for future protocols, this dissertation forms a detailed analysis of the ODMR spectroscopy of NV centers in nanodiamond powder and 13C-enriched diamond. These are two modalities that could make this transfer of polarization to nuclei in an external sample possible. Nanodiamond powder, for example, increases the number of NV defects exposed to an external sample by orders of magnitude relative to a single crystal sample. On the other hand, 13C in diamond could be used to mediate the transfer of polarization from NV centers to external nuclei, due to the fact that the 13C concentration can be tuned to be from 4 to 6 orders of magnitude greater than the NV center, and they would be closer to the surface where interaction with external spins is greatest. Such points make both media, nanodiamond powder and 13C-enriched diamond, attractive candidates for testing these ideas. Any information on how the spectroscopy and dynamics of the defect changes in both forms of diamond is therefore critical to any strategy of enhancing nuclear spin signal with NV centers in diamond.

This dissertation first describes inherent limitations in magnetic resonance techniques and how they could be improved with NV centers. NV center properties, properties of diamond, practical experimentation information, and detailed information on simulating spectra are all summarized. Results are presented on the current understanding of NV center behavior in these two forms of diamond. Finally, it is the goal of this dissertation to construct a system for testing polarization transfer from NV centers in diamond to an external sample. The progress made on developing this system, instructions for preparing the system for experiments, and current knowledge of troubleshooting the failure modes of the system are described in detail.