Designing solid-state quantum sensors for brain imaging

量子物理学是许多重要的生物医学成像技术的基础，如磁共振成像（MRI）或正电子发射断层扫描（PET）。脑磁图（MEG）是一种很有前途的新型无创成像技术，它基于测量颅骨外的微小磁场，已经在临床上使用，例如在计划脑部手术时用于区分健康组织和不健康组织。目前MEG主要采用超导量子干涉器件（squid）。这些传感器需要低温冷却，导致需要相当笨重的扫描仪，患者必须完全保持不动，这限制了许多潜在的应用。最近，基于原子蒸汽的新型传感器正在开发中。这些所谓的光泵磁强计（opm）的优点是它们可以在没有低温冷却的情况下运行，并且正在开始商业化。这种opm的一个限制是它们相对较低的空间分辨率，在几毫米的尺度上。基于金刚石中氮空位（NV）中心的固态传感器也不需要低温冷却，同时有望实现更高（微米级）的空间分辨率。它们开始在研究环境中应用于生物医学成像，但与opm相比处于早期发展阶段。我们的团队由NV中心的量子技术（Simon, Barclay）和金刚石纳米制造（barclays）以及神经科学（Simon）专家组成。利用这一专业知识，我们将设计基于NV中心的微腔增强吸收量子传感器芯片阵列。我们的设计将通过与SQUID和基于OPM的方法的广泛比较，基于nv系统的详细理论建模以及初始实验来获得信息。我们的目标是使这项技术能够成为应用于健康相关资助项目（如AICE）的基础，并产生商业利益（从目前的TRL 2到TRL 4）。

Quantum physics is the foundation for many important biomedical imaging techniques such as magnetic resonance imaging (MRI) or positron emission tomography (PET). Magnetoencephalography (MEG) is a promising new non-invasive imaging technique based on measuring the tiny magnetic field outside the skull, which is already being used clinically, e.g. for distinguishing healthy from unhealthy tissue when planning brain surgeries. Currently MEG typically uses superconducting quantum interference devices (SQUIDs). These sensors require cryogenic cooling, resulting in the need for quite bulky scanners, where patients have to hold completely still, which is limiting for many potential applications. More recently new types of sensors based on atomic vapors are being developed. These so-called optically pumped magnetometers (OPMs) have the advantage that they can operate without cryogenic cooling and are beginning to be commercialized. One limitation of such OPMs is their relatively low spatial resolution, which is on the scale of several millimeters. Solid-state sensors based on nitrogen-vacancy (NV) centers in diamond also do not require cryogenic cooling, while promising much higher (micron-scale) spatial resolution. They are starting to be applied to biomedical imaging in research settings, but are in an earlier stage of development compared to OPMs. Our team consists of experts on NV center based quantum technology (Simon, Barclay) and diamond nanofabrication (Barclay), as well as neuroscience (Simon). Leveraging this expertise, we will design chip-based arrays of micro-cavity enhanced absorptive quantum sensors based on NV centers. Our design will be informed by a broad comparison with SQUID and OPM based approaches, on detailed theoretical modeling of our NV-based systems, as well as on initial experiments. Our goal is to bring the technology to the point where it can be the basis for applications to health-related funding programs such as AICE and generate commercial interest (from currently TRL 2 to TRL 4).