Nitrogen-vacancy (NV) defect centers in diamond are promising solid-state magnetometers. Single centers allow for high-spatial-resolution field imaging but are limited in their magnetic field sensitivity. Using defect-center ensembles, sensitivity can be scaled with N when N is the number of defects. In the present work, we use an ensemble of N ～ 10 11 defect centers within an effective sensor volume of 8.5 × 10 ? 4 mm 3 for sensing at room temperature. By carefully eliminating noise sources and using high-quality diamonds with large NV concentrations, we demonstrate, for such sensors, a sensitivity scaling as 1 / t , where t is the total measurement time. The associated photon-shot-noise-limited magnetic-field sensitivity for ac signals of f = 20 kHz is 0.9 pT / Hz . For a total measurement time of 100?s, we reach a standard deviation of about 100?fT. Further improvements using decoupling sequences and material optimization could lead to fT / Hz sensitivity.
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机译：金刚石中的氮空位（NV）缺陷中心是有前途的固态磁力计。单个中心允许高空间分辨率场成像，但磁场灵敏度受到限制。使用缺陷中心集合，当n是缺陷的数量时，可以使用n缩放灵敏度。在目前的工作中，我们在有效的传感器容量为8.5×10的情况下使用N〜10 11个缺陷中心的集合？ 4 mm 3在室温下感测。通过仔细消除噪声源并使用具有大NV浓度的高质量钻石，我们向这种传感器展示，灵敏度缩放为1 / t，其中T是总测量时间。 F = 20kHz的AC信号的相关光子射击噪声限制磁场灵敏度为0.9pt / hz。对于100？S的总测量时间，我们达到约100架的标准偏差。使用去耦序列和材料优化的进一步改进可能导致FT / Hz灵敏度。
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