Defect engineering in diamond for magnetic field mapping and gradiometry

近年来，金刚石中的氮空位缺陷因其高度共格的自旋性质和方便的光学界面而引起了人们的极大兴趣。利用NV缺陷系综中的电子自旋进行的磁测量已被证明能够探测1pT；1pT-1/2的磁场，因此它们作为量子场传感器的使用正引起工业上的极大兴趣。已知正在使用NV中心构建商业磁测量系统的公司包括博世(导航系统)，几家组织正在开发基于NV的、分辨率为~10 nm的生物和物理科学磁成像系统。NV中心可以通过产生空位，然后进行热退火，使空位在晶体中扩散并与替代氮原子‘结合’而产生。在过去的两年里，我们已经证明，使用自适应像差校正的激光处理材料提供了一种高度可控的方法，可以在晶体中的所需位置产生空位。在随后的退火过程中，空位扩散到约100 nm，使得NV中心很有可能在所需的位置产生。在目前的实验中，单次NV产生的成功概率约为30%。通过迭代处理，应该可以产生用于高级磁学应用的规则的单个NV中心的3D网格。该项目：该学生将在工程系的Martin Booth小组中使用激光处理来开发单个NV中心的受控3D阵列。样品将使用光致发光光谱和材料部门Jason Smith小组的光学检测磁共振进行表征。具有立方阵列NV中心的样本将成为目标。我们将测量NV中心的电子自旋相干时间，以评估它们是否适合进行磁测量。最好的样品将用于演示3D磁场测绘和梯度测量。学生将受益于参与NQIT中心的两个小组的工作，并将接受激光处理、缺陷表征和磁测量方面的广泛培训。他们将与NQIT博士后帕特里克·索尔特(工程学)和山姆·约翰逊(材料)合作。他们将通过参加钻石科学和技术博士培训中心的单元获得深入的钻石培训。我们将安排学生和第六元素之间的密切互动，以优化材料以适应用户的应用。该项目属于量子技术公司的主题。

Nitrogen-vacancy defects in diamond have generated enormous interest in recent years for their highly coherent spin properties and convenient optical interface. Magnetometry using the electron spin in an ensemble of NV- defect has been shown to be capable of detecting fields of <1 pT Hz-1/2 such that their use as quantum field sensors is generating significant industrial interest. Companies known to be building commercial magnetometry systems with NV centres include Bosch (navigation systems), and several organisations are developing NV-based magnetic imaging systems with ~10nm resolution for biological and physical sciences. NV centres can be produced by generation of vacancies followed by thermal annealing to allow the vacancies to diffuse in the crystal and 'bind' with a substitutional nitrogen atom. In the past two years we have shown that laser processing of materials using adaptive aberration correction provides a highly controlled means of generating vacancies in a desired position in the crystal. Upon subsequent annealing the vacancies diffuse ~100 nm such that NV centres are produced with high probability in the desired location. Success probability of single NV generation in current experiments is around 30%. With iterative processing it should be possible to produce regular 3D grids of single NV centres for advanced magnetometry applications.The Project: The student will develop controlled 3D arrays of single NV centres using laser processing in Martin Booth's group in the department of Engineering. Samples will be characterised using photoluminescence spectroscopy and optically detected magnetic resonance in Jason Smith's group in the Department of Materials. Samples with cubic arrays of NV centres will be targeted. We will measure the electron spin coherence times of the NV centres to assess their suitability for magnetometry. The best samples will be used to demonstrate 3D magnetic field mapping and gradiometry.The student will benefit from working within two groups involved in the NQIT Hub and will receive extensive training in laser processing, defect characterisation and magnetometry. They will work with NQIT postdocs Patrick Salter (Engineering) and Sam Johnson (Materials). They will gain in-depth training in diamond by attending modules of the Centre for Doctoral Training in Diamond Science and Technology. We will arrange close interaction between the student and Element Six to optimise the materials towards user applications. The project falls under the theme of Quantum Technologies.