Due to its superior coherent and optical properties at room temperature, the nitrogen-vacancy (NV) center in diamond has become a promising quantum probe for nanoscale quantum sensing. However, the application of NV containing nanodiamonds to quantum sensing suffers from their relatively poor spin coherence times. Here we demonstrate energy efficient protection of NV spin coherence in nanodiamonds using concatenated continuous dynamical decoupling, which exhibits excellent performance with less stringent microwave power requirement. When applied to nanodiamonds in living cells we are able to extend the spin coherence time by an order of magnitude to the $T_1$-limit of up to $30\mu$s. Further analysis demonstrates concomitant improvements of sensing performance which shows that our results provide an important step towards in vivo quantum sensing using NV centers in nanodiamond.

中文翻译：

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保护活细胞中纳米金刚石的量子自旋相干性

由于其在室温下具有出色的相干性和光学特性，钻石中的氮空位（NV）中心已成为用于纳米级量子感测的有前途的量子探针。但是，将含有NV的纳米金刚石应用于量子感测的原因是它们的自旋相干时间相对较差。在这里，我们展示了使用级联连续动态去耦技术对纳米金刚石中NV自旋相干的高效节能保护，该技术表现出优异的性能，而对微波功率的要求不那么严格。当应用于活细胞中的纳米金刚石时，我们能够将自旋相干时间延长一个数量级，达到${Ť}_{\mathrm{1个}}$-上限为 $30\mu$s。进一步的分析表明，伴随着传感性能的提高，这表明我们的结果为使用纳米金刚石中的NV中心进行体内量子传感提供了重要的一步。