High-field DNP via Substitutional Nitrogen Impurities in Diamond

在化学系化学测量和成像项目的支持下，达特茅斯学院Ramanathan教授的团队正在努力提高核磁共振（NMR）光谱的灵敏度，这种光谱被广泛用于表征化学、材料和生物系统。核磁共振也是磁共振成像（MRI）的基础，它被广泛用于临床诊断和脑成像。Ramanathan小组开发的技术将使核磁共振研究能够在更小的样本量下进行，从而在纳米和微观尺度上研究新材料和化学。量子系统的控制是该项目的一个关键要素，是量子技术未来发展的核心，是国家战略优先事项。该项目将培养多名本科生和研究生，还将开发一个便携式磁共振实验室，向初高中学生和更广泛的社区展示基本的量子现象。室温动态核极化（DNP）通过取代氮或P1中心在金刚石将被用于超极化核自旋，无论是内部和外部的金刚石。目标是(i)确定产生最大DNP增强的样品特性和实验条件；（ii）通过P1中心与光激发NV中心的耦合，实现P1中心的超极化，进一步提高DNP的增强效果；（iii）研究利用钻石中的P1中心来增强钻石外核的信号，比较从电子到钻石外核的直接增强和通过钻石中13C核自旋传递的间接增强。这些研究将对中尺度磁共振方法的发展作出广泛贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Ramanathan's group at Dartmouth College is working to improve the sensitivity of nuclear magnetic resonance (NMR) spectroscopy which is widely used to characterize chemical, material, and biological systems. NMR also underpins magnetic resonance imaging (MRI) which is widely used for clinical diagnosis and brain mapping. The techniques developed by the Ramanathan group will enable NMR studies of smaller sample volumes allowing the study of novel materials and chemistry at the nano and microscale. The control of quantum systems, a key element of the project, is central to the future development of quantum technologies, a strategic national priority. The project will train multiple undergraduate and graduate students and will also develop a portable magnetic resonance laboratory to demonstrate fundamental quantum phenomena to middle- and high-school students and the broader community.Room-temperature dynamic nuclear polarization (DNP) via substitutional nitrogen or P1 centers in diamond will be used to hyperpolarize nuclear spins, both within and external to the diamond. The goals are to (i) identify the sample characteristics and experimental conditions that give rise to the largest DNP enhancements; (ii) further improve the DNP enhancements by hyperpolarizing the P1 centers via their coupling to optically-excited NV centers; and (iii) investigate the use of P1 centers in diamonds to enhance the signals of nuclei outside the diamond comparing both direct enhancement from electrons to nuclei outside the diamond and indirect enhancement where the transfer is relayed via the 13C nuclear spins in the diamond. These studies will contribute broadly to the development of methods for magnetic resonance at the mesoscale.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.