Magnetometers based on nitrogen-vacancy center ensembles in diamond have received considerable attention in recent years. However, their sensitivities are limited by low fluorescence collection efficiencies. With the introduction of some schemes, collection efficiencies of NV ensembles have been improved, but further improvement is still needed. In this Letter, we propose and demonstrate a fluorescence enhancing technique of reflective coating. By applying this technique, collection efficiencies already improved by other schemes will be further enhanced. With the assistance of a 100-nm-thick gold reflective film on the diamond surface, the fluorescence collection efficiency of an NV ensemble continuous-wave magnetometer utilizing a compound parabolic concentrator was further increased by 92%, and a magnetic field sensitivity of 164 pT / Hz at 0.99 to 77.98 Hz was achieved.

中文翻译：

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通过表面涂层提高氮空位集合磁力计的灵敏度

近年来，基于金刚石中氮空位中心系综的磁力计受到了相当大的关注。然而，它们的灵敏度受到低荧光收集效率的限制。随着一些方案的引入，NV ensemble的收集效率有所提高，但仍需进一步改进。在这封信中，我们提出并展示了一种反射涂层的荧光增强技术。通过应用该技术，已经由其他方案提高的收集效率将得到进一步提高。借助金刚石表面 100 nm 厚的金反射膜，使用复合抛物面聚光器的 NV 系综连续波磁强计的荧光收集效率进一步提高了 92%，磁场灵敏度为 164 pT /Hz 为 0。