Abstract
Bulk polarization can be strongly enhanced in diamond at room temperature based on the optical pumping of nitrogen-vacancy color centers. This effect was confirmed by irradiating single crystals at a field promoting anticrossings between electronic excited-state levels, followed by shuttling of the sample into an NMR setup and by subsequent detection. A nuclear polarization of —equivalent to the polarization achievable by thermal polarization at room temperature at fields of —was measured, and its bulk nature determined based on line shape and relaxation measurements. Positive and negative enhanced polarizations were obtained, with a generally complex but predictable dependence on the magnetic field during optical pumping. Owing to its simplicity, this room temperature polarizing strategy provides a promising new addition to existing nuclear hyperpolarization techniques.
- Received 25 November 2012
DOI:https://doi.org/10.1103/PhysRevLett.111.057601
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