Measurement with a deployable quantum magnetometer

双共振光泵磁力计（DR-OPMs）提供了一种强大而灵活的量子传感工具，可应用于医疗保健，地磁学，制造业和基础物理学。在过去的十年里，基础科学和组件微制造的发展大大增加了对这些现实世界应用的影响潜力。现在，OPM提供了毫微微特斯拉磁场分辨率（地球磁场中的十亿分之一灵敏度），只有低温SQUID磁力计才能提供类似的性能。然而，紧凑、便携、无制冷剂的OPM可用于SQUID磁强计尺寸和成本过高的许多应用中。OPM将应用于便携式心磁图和脑磁图，用于医学研究和诊断，其可扩展性和形状因子为便携式传感器阵列提供了新的功能。在地磁测量中，与广泛使用的感应式磁力计相比，OPM磁力测量相对于碱原子能级的固有校准是一个显著的优势，为勘测、国防和导航提供了免校准测量。OPM还可以配置为在亚MHz频带中对振荡磁场进行共振窄带检测，这得益于系统的频率不变限制量子噪声源，而不是广泛用于这些信号的经典约翰逊噪声限制电感传感器。这种可调谐的检测模式是低场超极化核磁共振在医药和化工生产中的关键技术。DR-OPMs的灵敏度和准确性在宇宙学轴子和畴壁的网络基础物理搜索中也有重要的应用。该项目将专注于开发和演示DR-OPM配置，以最大限度地提高特定应用的性能。这将需要在实验室中开发传感器模式和控制固件，旨在在优化的测试环境中以量子限制的精度工作，从而实现子系统优化和在现实世界应用中演示现场就绪原型。在实验室中开发技术和系统组件将与我们的最终用户网络合作，设计和演示现场系统。这项工作将建立在我们在DR-OPM读出和反馈方案方面的专业知识以及在专业子系统设计方面的能力，包括紧凑型激光光学系统和微加工碱蒸汽电池。增加子系统的性能和准备与DR-OPM操作中的新技术相结合，如数字自旋脉泽反馈方案，使这项研究处于关键的转化阶段。以实验室为基础的研究发展现在有可能在实地应用并迅速产生影响。越来越多的终端用户的兴趣是由越来越高的性能设备的技术演示驱动的。该项目将利用这些机会，展示和增强量子传感器在磁力测量中的影响，并将成为正在进行的量子技术开发的一个组成部分。

Double-resonance optically pumped magnetometers (DR-OPMs) offer a powerful and flexible quantum sensing tool with applications in healthcare, geomagnetics, manufacturing and fundamental physics. The last decade has seen developments in the underpinning science and component microfabrication which result in greatly increased potential for impact in these real-world applications. OPMs now offer Femtotesla magnetic field resolution (part-per-billion sensitivity in Earth's field), a regime in which only cryogenic SQUID magnetometers offer comparable performance. However, compact, portable, cryogen-free OPMs can be used in many applications where the size and cost of SQUID magnetometers is prohibitive. OPMs will be applied to portable magneto-cardiography and magneto-encephalography for medical research and diagnosis, where their scalability and form factor unlock new capabilities for portable sensor arrays. In geomagnetic measurements the intrinsic calibration of OPM magnetometry against alkali atomic energy levels is a significant advantage over widely-used inductive magnetometers, offering calibration-free measurement for surveying, defence and navigation. OPMs can also be configured for resonant narrowband detection of oscillating magnetic fields in the sub-MHz band, benefiting from the system's frequency-invariant limiting quantum noise sources, rather than the classical Johnson-noise-limited inductive sensors widely used for these signals. This tuneable detection mode is a key technology for low-field hyperpolarised NMR in pharmaceutical and chemical manufacture. The sensitivity and accuracy of DR-OPMs also has important applications in networked fundamental physics searches for cosmological axions and domain walls. This project will focus on the development and demonstration of DR-OPM configurations tailored to maximise performance in specific applications. This will entail the development of sensor modes and control firmware in the laboratory, aiming to work at quantum-limited precision in an optimised test environment, leading on to sub-system optimisation and demonstration of field-ready prototypes in real-world applications. The development of techniques and system components in the lab will lead forward to the design and demonstration of field systems in collaboration with our network of end users. This work will build on our expertise in DR-OPM readout and feedback schemes and demonstrated capability in specialised subsystem design, including compact laser-optical systems and micro-fabricated alkali vapour cells. The combination of increasing subsystem performance and readiness with new techniques in DR-OPM operation, such as digital spin maser feedback schemes, places this research at a critical translational stage. Laboratory-based research developments now have potential for field application and rapid impact. Increasing end-user interest is driven by technology demonstration with increasingly high-performance devices. This project will exploit these opportunities, demonstrating and enhancing the impact of quantum sensors in magnetometry, and it will be an integral part of ongoing quantum technology development.