Spectroscopy with Quantum Sensors at the Nanoscale

非技术描述：光谱学在许多物理环境中是一个强大的工具，应用范围从基本物理性质的分析到化学、材料科学和生物成像中的样品分析。该项目旨在将光谱学中使用的强大技术转化为一种新型的传感器，基于钻石中缺陷的量子特性。这些光学活性缺陷(色心)具有相关的电子自旋，对磁场和电场、温度、压力等很敏感。该项目将开发为量子领域量身定做的光谱技术，可以在钻石中使用这些纳米级传感器。该项目将特别侧重于实现噪声光谱学，即测量材料和生物科学中普遍存在的随机场(特别是磁场)的空间和时间相关性。通过将适用于量子传感器的新噪声光谱技术与量子传感器本身的纳米级分辨率相结合，新的量子噪声光谱技术将能够在以前无法达到的范围内测量场。此外，该项目将为研究生和本科生提供广泛领域的培训机会，从磁共振到量子信息，以及电子和量子光学的实验技能。此外，该项目还将开展外联活动，包括钻石传感器演示。技术描述：利用单个量子系统的新型纳米传感器的出现有望为我们对纳米电子学、光子学和磁性设备及其潜在物理现象的基本理解带来曙光。这些新颖的量子探测器，如钻石中的氮空位中心，可以在以前无法达到的条件和空间分辨率下运行：它们可以非常接近感兴趣的系统，以纳米级的分辨率测量微小的磁场(或电场)。经过近年来的第一次原理验证，这些传感器即将成为探索电磁设备和材料的变革性工具。为了实现这一目标，这些自旋传感器不仅应该能够测量给定场的大小，更重要的是，它应该能够测量其时间和空间相关性，这些相关性携带了关于潜在物理特性的大部分信息。该项目的目标是将与钻石自旋相关的量子传感器转变为强大的光谱仪，能够在纳米尺度上探测由于生物或磁性材料动力学而产生的磁场的时空相关性，具有以前无法达到的空间分辨率和灵敏度。此外，表征噪声频谱对于设计有效的策略来抵消新兴量子设备中的退相干至关重要。该项目将结合噪声光谱学和量子数字滤波方面的专业知识，通过量子纳米传感器实现有效和完整的噪声光谱重建。最终目标是发展一个新的量子数字噪声光谱领域，基于噪声光谱和沃尔什数字滤波函数的完整基础，并将其应用于磁性样品的增强传感，以及它们的结构和时空相关性。具有NV中心的钻石量子数字噪声光谱也将与NV的超分辨率寻址相结合，应用于生物样品的纳米级磁共振成像和测量磁性2D材料的空间噪声相关性。这样的实验可以为被测样品的结构和动力学提供新的线索，从而对生物功能和磁性相变的普遍性质产生新的见解。

Non-Technical Description: Spectroscopy is a powerful tool in many physical settings, with applications ranging from analysis of basic physical properties to sample analysis in chemistry, material science and bio-imaging. This project aims at translating the powerful techniques used in spectroscopy to a novel type of sensors, based on the quantum properties of defects in diamond. These optically active defects (color centers) have an associated electronic spin that is sensitive to magnetic and electric fields, temperature, pressure, etc. The project will develop spectroscopic techniques, tailored to the quantum realm, that can be implemented with these nanoscale sensors in diamond. In particular, the project will focus on achieving noise spectroscopy, that is, measuring spatial and temporal correlation of random fields (in particular magnetic fields), which are ubiquitous in materials and biological sciences. By combining novel noise spectroscopic techniques that work for quantum sensors, with the nanoscale resolution of the quantum sensors themselves, the novel quantum noise spectroscopy technique will be able to measure fields at scales not previously accessible. In addition, the project will provide opportunities for training graduate and undergraduate students in broad areas, ranging from magnetic resonance, to quantum information, as well as experimental skills in electronics and quantum optics. The project will in addition develop outreach activities, including a diamond sensor demo. Technical Description: The advent of novel nanoscale sensors exploiting individual quantum systems promise to shed light into our fundamental understanding of nano-electronics, photonics and magnetics devices, and their underlying physical phenomena. These novel quantum probes, such as the Nitrogen-Vacancy center in diamond, can perform in conditions and with a spatial resolution previously inaccessible: they can be brought very close to the system of interest and measure minute magnetic (or electric) fields with nanoscale resolution. After the first proof-of-principle demonstrations in recent years, these sensors are on the verge of becoming transformative tools for the exploration of electromagnetic devices and materials. To reach this goal, these spin sensors should be able not only to measure the magnitude of a given field, but more importantly its temporal and spatial correlations that carry most of the information about underlying physical properties. The goal of this project is to transform quantum sensors associated with spins in diamond into powerful spectrometers, able to detect spatiotemporal correlations of magnetic fields at the nanoscale due to, e.g., biological or magnetic materials dynamics, with a spatial resolution and sensitivity previously unattainable. Moreover, characterizing the noise spectrum is critical for devising effective strategies to counteract decoherence in emerging quantum devices. This project will combine expertise on noise spectroscopy and on quantum digital filtering to achieve an efficient and complete reconstruction of the noise spectrum via a quantum nanoscale sensor. The ultimate goal is to develop a new field of quantum digital noise spectroscopy, based on noise spectroscopy combined with the complete basis of Walsh digital filtering functions, and applying it to enhanced sensing of magnetic samples, and their structure and spatiotemporal correlations. Quantum digital noise spectroscopy with NV centers in diamond, also combined with super-resolution addressing of NVs, will be applied to nanoscale magnetic resonance imaging of biological samples and to measure spatial noise correlations of magnetic 2D materials. Such experiments could shed new light on the structure and dynamics of the measured samples, leading to new insights in biological functions and in universal properties of magnetic phase transitions.