Hosokawa Fumio, Sawada Hidetaka, Shinkawa Takao, Sannomiya Takumi
BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo, Japan; Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503, Japan.
JEOL (UK) Ltd., JEOL House, Silver Court, Watchmead, Welwyn Garden City, Herts AL7 1LT, England.
Ultramicroscopy. 2016 Aug;167:11-20. doi: 10.1016/j.ultramic.2016.04.010. Epub 2016 Apr 27.
The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field's components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field's derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope.
针对像差校正透射电子显微镜，推导了包含高达六重像散的空间相干公式。使用新推导的公式计算具有几种残余像差的线性成像传递函数。根据像差的对称性和起源，计算出的传递函数呈现出特征对称性。源自场分量且沿z方向具有均匀性的像差，即n重像散，显示出相干性的旋转对称衰减。源自场关于z的导数的像差，如彗差、星芒和三叶像差，显示出非旋转对称衰减。证实了奇对称波像差通过空间相干性对图像衰减有影响。通过使用像差校正电子显微镜的空间相干性，展示了血红蛋白和Si [211]的图像模拟示例。
