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，达特茅斯学院的Ramanathan教授小组正在努力提高核磁共振（NMR）光谱的灵敏度，该光谱被广泛用于表征化学，材料和生物系统。 核磁共振还支持磁共振成像（MRI），它被广泛用于临床诊断和脑成像。 Ramanathan小组开发的技术将使更小样品体积的NMR研究成为可能，从而可以在纳米和微米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，这是国家的战略重点。 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，向初中和高中学生以及更广泛的社区演示基本量子现象。通过金刚石中的替代氮或P1中心的室温动态核极化（DNP）将用于超自旋核自旋，包括金刚石内部和外部。 目标是（i）确定产生最大DNP增强的样品特征和实验条件;（ii）通过P1中心与光激发NV中心的耦合使P1中心超极化来进一步改善DNP增强;以及（iii）研究使用钻石中的P1中心来增强钻石外部的核的信号，比较从电子到钻石外部的核的直接增强，钻石和间接增强，其中转移通过钻石中的13 C核自旋进行中继。 这些研究将为中尺度磁共振方法的发展做出广泛贡献。该奖项反映了NSF的法定使命，并被认为值得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来支持。

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.