Single shot readout of NV detectors for chemically relevant single-molecule magnetic resonance.

该项目的目的是在钻石的NV中心检测到的纳米级核磁共振和EPR实验中，获得比最先进水平高一个数量级的灵敏度和两个数量级的光谱分辨率，并利用这一进展来检测纳米核磁共振实验中的化学相关光谱特征。这一改进将通过将两种最新开发的技术相结合来实现，以便在纳米级磁共振实验中更有效地读出NV中心的电子自旋：通过核量子存储器对NV中心的单次自旋读出[1]和通过自旋-电荷转换高效的荧光读出[2]。核量子存储器单次激发读出是一种克服NV中心电子自旋荧光读出探测效率低的技术。它将采集时间减少两个数量级，或者通过在例如由NV中心的氮核自旋形成的量子存储器中存储和重复读出测量结果，将灵敏度提高一个数量级。自旋-电荷转换是一种相关的高效自旋读出技术。它利用NV中心的自旋依赖的光电离进入其中性电荷状态，这可以通过荧光读出以高保真的方式检测到。在该项目中，这些技术将在钻石表面以下几纳米的浅NV中心实施，因为它们是探测外部电子和核自旋所必需的。随后，应将它们组合成一种融合了任一实现的优点的技术。最后，应利用灵敏度的提高来演示纳米磁共振实验中化学相关光谱特征的光谱，如化学位移或J-耦合。

The project aims at to gain an order of magnitude in sensitivity and two orders of magnitude in spectral resolution over the state of the art in nanoscale NMR and EPR experiments detected by NV centers in diamond and to exploit this progress for the detection of chemically relevant spectral features in nano-NMR experiments. This improvement shall be enabled by combining two recently developed techniques for more efficient readout of the NV center electron spin into nanoscale magnetic resonance experiments: single shot spin readout of the NV center by nuclear quantum memories [1] and efficient fluorescence readout by spin-charge conversion [2]. Single shot readout by nuclear quantum memories is a technique to overcome the low detection efficiency of fluorescence readout of the NV center electron spin. It reduces acquisition times by two orders of magnitude or, equivalently, boosts sensitivity by one order of magnitude by storage and repetitive readout of a measurement result in a quantum memory, formed e.g. by the NV center nitrogen nuclear spin. Spin-charge conversion is a related technique for efficient spin readout. It exploits spin-dependent photoionization of the NV center into its neutral charge state, which can be detected with high fidelity by fluorescence readout. In the project, these techniques shall be implemented on shallow NV centers few nanometers below the diamond surface as they are required for sensing of external electron and nuclear spins. Subsequently, they shall be combined to a technique merging the advantages of either implementation. Finally, the improvement in sensitivity shall be exploited to demonstrate spectroscopy of chemically relevant spectral features in a nano-magnetic resonance experiment, such as chemical shifts or J-couplings.