Aberration-corrected electron microscopy can resolve the smallest atomic bond lengths in nature. However, the high-convergence angles that enable spectacular resolution in two dimensions have unknown three-dimensional (3D) resolution limits for all but the smallest objects ($<\sim 8$ nm). We show aberration-corrected electron tomography offers new limits for 3D imaging by measuring several focal planes at each specimen tilt. We present a theoretical foundation for aberration-corrected electron tomography by establishing analytic descriptions for resolution, sampling, object size, and dose—with direct analogy to the Crowther-Klug criterion. Remarkably, aberration-corrected scanning transmission electron tomography can measure complete 3D specimen structure of unbounded object sizes up to a specified cutoff resolution. This breaks the established Crowther limit when tilt increments are twice the convergence angle or smaller. Unprecedented 3D resolution is achievable across large objects. Atomic 3D imaging (1 Å) is allowed across extended objects larger than depth of focus (e.g., $>20$ nm) using available microscopes and modest specimen tilting ($<3^{\circ }$). Furthermore, aberration-corrected tomography follows the rule of dose fractionation where a specified total dose can be divided among tilts and defoci.

中文翻译：

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像差校正电子断层扫描的三维分辨率和剂量限制

像差校正电子显微镜可以解决自然界中最小的原子键长度。但是，可以在二维中实现出色分辨率的高会聚角对于除最小物体外的所有物体，都具有未知的三维（3D）分辨率极限（$<〜8$nm）。我们显示，像差校正电子断层扫描通过测量每个样品倾斜处的多个焦平面，为3D成像提供了新的限制。我们通过建立分辨率，采样，物体大小和剂量的解析描述，直接类似于Crowther-Klug准则，为像差校正电子层析成像提供了理论基础。值得注意的是，像差校正的扫描透射电子断层扫描可以测量完整的3D样本结构，其无边界物体尺寸可达指定的截止分辨率。当倾斜增量是会聚角的两倍或更小时，这会破坏建立的Crowther极限。在大型物体上可以实现前所未有的3D分辨率。可以在大于焦点深度的扩展对象上进行原子3D成像（1Å），例如$>20$ nm），并使用适当的样品倾斜度（$<3^{\circ }$）。此外，像差校正层析成像遵循剂量分级的规则，其中可以将特定的总剂量分为倾斜和散焦。