Nitrogen vacancy (NV) centers in diamond have attracted considerable recent interest for use in quantum sensing, promising increased sensitivity for applications ranging from geophysics to biomedicine. Conventional sensing schemes involve monitoring the change in red fluorescence from the NV center under green laser and microwave illumination. Due to the strong fluorescence background from emission in the NV triplet state and low relative contrast of any change in output, sensitivity is severely restricted by a high optical shot noise level. Here, we propose a means to avoid this issue, by using the change in green pump absorption through the diamond as part of a semiconductor external cavity laser run close to the lasing threshold. We show that theoretical sensitivity to the magnetic field on the pT/$\sqrt{\mathrm{Hz}}$ level is possible using a diamond with an optimal density of NV centers. We discuss the physical requirements and limitations of the method, particularly the role of amplified spontaneous emission near threshold and explore realistic implementations using current technology.

中文翻译：

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利用外腔激光器中金刚石氮空位吸收绿光的激光阈值磁力测量

金刚石中的氮空位 (NV) 中心最近在量子传感中引起了相当大的兴趣，有望提高从地球物理学到生物医学等应用的灵敏度。传统的传感方案包括在绿色激光和微波照射下监测来自 NV 中心的红色荧光的变化。由于 NV 三重态发射的强荧光背景和输出的任何变化的低相对对比度，灵敏度受到高光学散粒噪声水平的严重限制。在这里，我们提出了一种避免这个问题的方法，通过使用通过金刚石的绿色泵浦吸收的变化作为接近激光阈值的半导体外腔激光器的一部分。我们表明对 pT/ 上的磁场的理论敏感性$\sqrt{\mathrm{赫兹}}$使用具有最佳 NV 中心密度的金刚石可以达到更高的水平。我们讨论了该方法的物理要求和局限性，特别是接近阈值的放大自发辐射的作用，并探索使用当前技术的现实实现。