Abstract: Dynamic nuclear polarization (DNP) is an experimental technique that transfers electron spin polarization to nuclear spins by microwave irradiation at or near the electron Larmor frequency. DNP offers a method of cooling an ensemble of nuclear spins, potentially bringing them close to their ground state. In the context of nuclear magnetic resonance (NMR), this cooling results in a dramatic increase in the observed NMR signal by
a factor of up to γe/γn, the ratio of the electron and nuclear gyromagnetic ratios. This increase in sensitivity opens the door to using NMR to study sample-limited systems, such as surfaces and novel 2-D materials.

Probing the physics of these systems at ever smaller scales requires a significant advance in DNP methodology, as current signal enhancements are often up to an order of magnitude smaller than the theoretical limit. My thesis work describes my contributions to advancing both instrumentation and DNP methodology to improve the efficiency of the electron to nuclear polarization transfer in DNP experiments, leading towards studying
the physics of low-dimensional systems. I describe the design and construction of a novel 94 GHz millimeter wave transmission scheme for both DNP and longitudinally detected-ESR experiments at 3.34 T. These developments include the addition of modulated microwaves at 94 GHz, which enables improved electron spin excitation schemes. Using these capabilities, I demonstrate the dynamical probing of a low-dimensional system: adsorption of water on the surface of silicon particles. I also introduce a new frequency modulated microwave driving scheme that considers the ESR properties of the DNP sample and demonstrate that this driving scheme further increases the efficiency of electron to nuclear polarization transfer, yielding a higher sensitivity and making NMR a more feasible tool for studying the physics of low-dimensional solids.