Li Shuo, Bai Dongbi, Capelli Marco, Sun Qiang, Afshar V Shahraam, Simpson David A, Foster Scott, Ebendorff-Heidepriem Heike, Gibson Brant C, Greentree Andrew D
Opt Express. 2021 May 10;29(10):14425-14437. doi: 10.1364/OE.417825.
Diamonds containing the negatively charged nitrogen-vacancy centre are a promising system for room-temperature magnetometry. The combination of nano- and micro-diamond particles with optical fibres provides an option for deploying nitrogen-vacancy magnetometers in harsh and challenging environments. Here we numerically explore the coupling efficiency from nitrogen-vacancy centres within a diamond doped at the core/clad interface across a range of commercially available fibre types so as to inform the design process for a diamond in fibre magnetometers. We determine coupling efficiencies from nitrogen-vacancy centres to the guided modes of a step-index fibre and predict the optically detected magnetic resonance (ODMR) generated by a ensemble of four nitrogen-vacancy centres in this hybrid fibre system. Our results show that the coupling efficiency is enhanced with a high refractive index difference between the fibre core and cladding and depends on the radial position of the nitrogen-vacancy centres in the fibre core. Our ODMR simulations show that due to the preferential coupling of the nitrogen-vacancy emission to the fibre guided modes, certain magnetometry features such as ODMR contrast can be enhanced and lead to improved sensitivity in such diamond-fibre systems, relative to conventional diamond only ensemble geometries.
含有带负电荷氮空位中心的钻石是一种很有前景的室温磁力测量系统。纳米和微米级钻石颗粒与光纤的结合为在恶劣和具有挑战性的环境中部署氮空位磁力计提供了一种选择。在这里，我们通过数值模拟研究了在一系列商用光纤类型中，位于纤芯/包层界面处掺杂的钻石内氮空位中心的耦合效率，以便为光纤磁力计中的钻石设计过程提供参考。我们确定了氮空位中心与阶跃折射率光纤的导模之间的耦合效率，并预测了这种混合光纤系统中四个氮空位中心的集合产生的光探测磁共振（ODMR）。我们的结果表明，耦合效率随着纤芯和包层之间的高折射率差而提高，并且取决于氮空位中心在纤芯中的径向位置。我们的ODMR模拟表明，由于氮空位发射优先耦合到光纤导模，与传统的仅由钻石组成的集合几何结构相比，某些磁力测量特征（如ODMR对比度）可以得到增强，并导致这种钻石-光纤系统的灵敏度提高。
