Department of Physics, University of California, Santa Barbara, CA 93106, USA.
Proc Natl Acad Sci U S A. 2012 Aug 21;109(34):13493-7. doi: 10.1073/pnas.1211311109. Epub 2012 Aug 6.
Using an optical tweezers apparatus, we demonstrate three-dimensional control of nanodiamonds in solution with simultaneous readout of ground-state electron-spin resonance (ESR) transitions in an ensemble of diamond nitrogen-vacancy color centers. Despite the motion and random orientation of nitrogen-vacancy centers suspended in the optical trap, we observe distinct peaks in the measured ESR spectra qualitatively similar to the same measurement in bulk. Accounting for the random dynamics, we model the ESR spectra observed in an externally applied magnetic field to enable dc magnetometry in solution. We estimate the dc magnetic field sensitivity based on variations in ESR line shapes to be approximately 50 μT/√Hz. This technique may provide a pathway for spin-based magnetic, electric, and thermal sensing in fluidic environments and biophysical systems inaccessible to existing scanning probe techniques.
我们使用光镊装置，在溶液中对纳米金刚石进行三维控制，并同时读出金刚石中氮空位色心的基态电子自旋共振（ESR）跃迁。尽管氮空位中心在光阱中处于运动和随机取向状态，但我们在测量的 ESR 光谱中观察到明显的峰，其与体相中相同的测量结果定性相似。考虑到随机动力学，我们对在外部施加磁场中观察到的 ESR 光谱进行建模，以在溶液中实现直流磁强计。我们根据 ESR 线形状的变化来估计直流磁场灵敏度，大约为 50 μT/√Hz。该技术可能为在现有扫描探针技术无法到达的流体环境和生物物理系统中进行基于自旋的磁、电和热传感提供一种途径。
