Direct 3D Imaging of Molecular Structure: Quantum Sensing and Control

加尔比尼科学界最古老和最持久的梦想之一就是以埃为尺度的分辨率，以原位、三维、无损的方式直接观察分子结构。这种成像技术将立即满足纳米工程、材料科学、分子生物学和医学的迫切需求。这项研究的目的就是创造这样一种技术。所提出的方法是核磁共振力显微镜MRFM，由提出者于1991年构思，专门作为3D分子成像的手段。核磁共振成像术的中心概念是将三维磁共振成像与角度尺度的显微镜检查相结合。1992年，在丹·鲁格的IBM团队的合作下，MRFM首次进行了实验演示。这个NSF计划的具体目标是：(1)展示3D MRFM成像的纳米尺度分辨率；(2)实现对MRFM环境中电子和质子自旋弛豫的可靠的、经实验验证的理解；(3)将现有的最优控制和估计的设计原则扩展到适用于单自旋成像的量子环境。所提出的方法是：(1)通过力、参数和多路成像实验来验证和校准提出者新完成的3D MRFM扫描仪；(2)设计和运行下一代自适应数字控制器，包括最优控制、估计和诊断算法；以及(3)测量各种目标样品中的电子和质子自旋弛豫。提议打开一个新的成像窗口，进入基本上未被观察到的3D分子结构世界，将彻底改变纳米工程、材料科学、生物、医学和工程教育领域。

0097544GarbiniOne of the oldest and most enduring dreams of the scientific communityis to directly observe molecular structure nondestructively, in situ, inthree dimensions, with Angstrom-scale resolution. Such an imagingtechnology would immediately address urgent needs in nanoscaleengineering, materials science, molecular biology, and medicine. Theobjective of the proposed research is to create such a technology.The proposed method is magnetic resonance force microscopy MRFM, whichwas conceived in 1991, by the proposers specifically as a means for 3Dmolecular imaging. The central concept of MRFM is to combinethree-dimensional magnetic resonance imaging with angstrom-scale probemicroscopy. MRFM was first experimentally demonstrated in 1992 incollaboration with Dan Rugar's IBM group. Subsequently, MRFM hasdeveloped into a worldwide sensing and imaging research effort.The specific aims of this NSF proposal are to: (1) demonstratenanoscale resolution in 3D MRFM imaging; (2) achieve a reliable,experimentally validated understanding of electron and proton spinrelaxation in the MRFM environment; and (3) extend present designprinciples for optimal control and estimation to the quantum environmentappropriate to single spin imaging.The proposed means are to: (1) validate and calibrate the proposers'newly completed 3D MRFM scanner, via force, parametric, and multipleximaging experiments; (2) design and operate a next-generation adaptivedigital controller, incorporating optimal control, estimation, anddiagnostic algorithms; and (3) survey electron and proton spinrelaxation in a variety of target samples.The proposed opening of a new imaging window onto the largely unobservedworld of 3D molecular structure will revolutionize the fields ofnanoscale engineering, materials science, biology, medicine, andengineering education.