Dartmouth Events

Abstract: A broad effort is underway to improve the sensitivity of nuclear magnetic resonance through the use of dynamic nuclear polarization. Nitrogen-vacancy (NV) centers in diamond offer an appealing platform because these paramagnetic defects can be optically polarized efficiently at room temperature. This presentation surveys alternative NV-based 13C spin polarization protocols, with emphasis on a recent scheme designed for powder geometries. Through experimental, analytical, and numerical work, we show that 13C spins polarize efficiently for virtually all orientations of the NV axis relative to the applied magnetic field and over a broad range of hyperfine couplings. We will also discuss the mechanics of the polarization of 13C spins in single crystals in the absence of microwave excitation, with attention to the interplay that emerges between spin cross-relaxation and mechanical rotation of the crystal as a whole.