STTR Phase I: Nanophotonic magnetic-resonance spectrometer for chemical trace analysis

这个小型企业技术转让（STTR）第一阶段项目将导致光学检测磁共振传感器的制造和验证，用于确定微量液体和粉末样品的化学成分。从国防取证和环境安全，到材料合成和石油勘探，这在许多行业都至关重要。对痕量分析物的化学特异性检测的渴望刺激了一个庞大而多样化的市场的增长，由拉曼光谱和高场台式核磁共振（NMR）等技术提供服务。这些已经是相当大的市场（约10亿美元），根据产品类型和地理位置的不同，年增长率为5-10%。这种新型传感器将对公共安全和国防产生直接而广泛的影响，例如在机场和边境安全检查中。对少量具有潜在威胁的化学品和材料进行可靠的检测和分析对于同时满足日益增长的安全需求和消除对大量分析物进行测试的需要至关重要。根据可在教学和研究环境中使用的可负担得起的交钥匙系统的预期开发，还预计会对科学教育产生影响。这个项目的智力价值在于应用金刚石固态缺陷的基本物理原理来制造一种具有化学痕量分析所需的独特性能的装置。与许多核磁共振系统不同，该光谱仪在环境温度下工作，在小型永磁体容易产生的磁场范围内工作，样品体积为亚微升。分析物通过微流控芯片传送到由掺杂氮空位（NV）色心的纳米结构金刚石组成的传感器区域。通过施加激光和微波脉冲，分析物的核磁化过程产生的磁场被编码为NV荧光信号。对荧光信号进行分析，得到被分析物的核磁共振谱，并根据已建立的文库提取化学成分。该平台绕过了传统基于线圈的方法阻碍核磁共振灵敏度的两个常见问题。首先，它不依赖于热极化，因此可以在环境温度和低磁场下工作，而不会影响信号强度。其次，它使用磁力计直接测量核磁化强度，从而避免了灵敏度差的问题，这是频率相关磁通检测的基础。

This Small Business Technology Transfer (STTR) Phase I project will result in the fabrication and validation of an optically-detected magnetic resonance sensor for determining the chemical composition of trace quantities of liquid and powder samples. This is critical in numerous industries ranging from defense forensics and environmental safety, to materials synthesis and petroleum exploration. The desire for chemically-specific detection of trace analytes has spurred the growth of a large and diverse market, served by techniques such as Raman spectroscopy and high-field benchtop nuclear magnetic resonance (NMR). These are already sizeable markets (on the order of $1 billion) with annual growth rates of 5-10%, depending on product type and geography. This new sensor will have a direct and broad impact on public security and defense, for example in airport and border security checks. The reliable detection and analysis of small quantities of potentially-threatening chemicals and materials are essential for simultaneously meeting the increased demands for security and eliminating the need to test large quantities of analyte. An impact on science education is also anticipated, based on the anticipated development of an affordable turnkey system, which can be used in instructional and research settings.The intellectual merit of this project lies in the application of the basic physics of solid-state defects in diamond to create a device with unique properties desirable for chemical trace analysis. Unlike many NMR systems, this spectrometer operates at ambient temperature, in a range of magnetic fields easily generated by small permanent magnets, and with sub-microliter sample volumes. The analyte is delivered via a microfluidic chip to a sensor region consisting of a nanostructured diamond doped with nitrogen-vacancy (NV) color centers. By applying pulses of laser light and microwaves, the magnetic field from the analyte's precessing nuclear magnetization becomes encoded in the NV fluorescence signal. Analysis of the fluorescence signal reveals the NMR spectrum of the analyte, from which the chemical composition can be extracted based on established libraries. This platform bypasses two common problems that hinder NMR sensitivity using traditional coil-based approaches. First, it does not rely on thermal polarization and thus allows operation at ambient temperature and low magnetic field without affecting the signal strength. Second, it uses a magnetometer to directly measure the nuclear magnetization and thus avoids the poor sensitivity that is fundamental to frequency-dependent flux detection.