Super-Resolution Diamond Magnetic Microscopy of Superparamagnetic Nanoparticles
Super-Resolution Diamond Magnetic Microscopy of Superparamagnetic Nanoparticles
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DOI：
10.1021/acsnano.3c12283
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发表时间：
2024-02-19
期刊：
影响因子：
17.1
通讯作者：
Acosta，Victor M.
中科院分区：
文献类型：
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作者：
Mosavian，Nazanin;Hubert，Forrest;Acosta，Victor M.
基于金刚石中氮空位(NV)中心的扫描探针和广场磁显微镜使生物学和材料研究取得了进展，但每种方法都有缺点。在这里，我们实现了一种替代的方法，基于光学控制钻石表面附近致密层中NV中心的电荷状态，用于纳米尺度的磁性显微镜。通过将甜甜圈光束超分辨率技术与光学检测磁共振光谱相结合，我们成像了单个30纳米氧化铁纳米颗粒产生的磁场。磁性显微镜的横向空间分辨率为∼100 nm，它可以从粒子间距为∼190 nm的纳米粒子簇中分辨出单个磁偶极子的特征。由于光学点扩散函数较窄，NV中心较浅，磁特征幅值比共聚焦磁镜法大一个数量级以上。我们分析了磁性纳米颗粒图像和灵敏度与显微镜空间分辨率的关系，结果表明，纳米颗粒检测的信噪比不会随着空间分辨率的提高而降低。我们找出了限制当前性能的背景荧光源，包括钻石的二阶拉曼发射和不完善的NV电荷态控制。我们的方法使用<；10 mW的激光功率，可以通过图案化照明来并行化，为纳米尺度的磁性成像引入了一种很有前途的格式。
Scanning-probe and wide-field magnetic microscopes based on nitrogen-vacancy (NV) centers in diamond have enabled advances in the study of biology and materials, but each method has drawbacks. Here, we implement an alternative method for nanoscale magnetic microscopy based on optical control of the charge state of NV centers in a dense layer near the diamond surface. By combining a donut-beam super-resolution technique with optically detected magnetic resonance spectroscopy, we imaged the magnetic fields produced by single 30 nm iron-oxide nanoparticles. The magnetic microscope has a lateral spatial resolution of ∼100 nm, and it resolves the individual magnetic dipole features from clusters of nanoparticles with interparticle spacings down to ∼190 nm. The magnetic feature amplitudes are more than an order of magnitude larger than those obtained by confocal magnetic microscopy due to the narrower optical point-spread function and the shallow depth of NV centers. We analyze the magnetic nanoparticle images and sensitivity as a function of the microscope’s spatial resolution and show that the signal-to-noise ratio for nanoparticle detection does not degrade as the spatial resolution improves. We identify sources of background fluorescence that limit the present performance, including diamond second-order Raman emission and imperfect NV charge state control. Our method, which uses <10 mW laser power and can be parallelized by patterned illumination, introduces a promising format for nanoscale magnetic imaging.