Title: A fiber integrated N-V diamond magnetometer compatible with commercial endoscopic systems Show Chinese title

Title: 与商用内窥镜系统兼容的光纤集成氮-空位金刚石磁强计

Abstract: Nitrogen-vacancy (N-V) center in diamond provides a robust, solid-state platform for magnetic field measurements at room temperature. To harness its potential in inspecting inaccessible regions, here we present a compact endoscopic configuration of an N-V diamond-based magnetometer. The endoscopic magnetometer was developed by integrating a large-core optical fiber with a bulk N-V diamond for laser excitation and photoluminescence (PL) collection. The diamond and fiber were specially shaped to enhance PL collection through the fiber. Additionally, a 3D-printed endoscope head was employed to facilitate alignment of the bias magnetic field along the N-V axis. A magnetic field sensitivity of approximately 3 nT/Hz$^{1/2}$ was achieved by using cw-magnetometry measurements. The endoscope diameter was restricted to 10 mm to match the dimensions of most commercial endoscopes. The magnetic field non-uniformity caused by the small separation between the diamond and the magnet in the endoscope head limited the overall sensitivity. It could be further improved to 0.85 nT/Hz$^{1/2}$ by using a magnet placed at a sufficient distance outside the endoscope head. Our endoscopic design is mechanically stable and provides additional opportunities for integrating other functionalities into the probe head as needed. Show Chinese abstract

Abstract: 氮-空位（N-V）中心在金刚石中提供了一个坚固的固态平台，用于室温下的磁场测量。 为了利用其在检查不可达区域方面的潜力，这里我们提出了一种基于N-V金刚石的紧凑内窥镜配置。 通过将大芯径光纤与块状N-V金刚石集成，开发了内窥镜磁强计，用于激光激发和光致发光（PL）收集。 金刚石和光纤经过特殊设计，以通过光纤增强PL收集。 此外，采用3D打印的内窥镜头部，以促进偏置磁场沿N-V轴对齐。 通过使用连续波磁强计测量，实现了大约3 nT/Hz$^{1/2}$的磁场灵敏度。 内窥镜直径被限制为10毫米，以匹配大多数商用内窥镜的尺寸。 由于内窥镜头部中金刚石和磁铁之间的小间距导致的磁场不均匀性，限制了整体灵敏度。 通过将磁铁放置在内窥镜头部外部足够远的位置，可以进一步提高到0.85 nT/Hz$^{1/2}$。 我们的内窥镜设计在机械上是稳定的，并且提供了额外的机会，根据需要将其他功能集成到探头头部中。