title: Quantitative evaluation of temporal partial coherence using 3D Fourier transforms of through-focus TEM images.
abstract: We evaluate the temporal partial coherence of transmission electron microscopy (TEM) using the three-dimensional (3D) Fourier transform (FT) of through-focus images. Young's fringe method often indicates the unexpected high-frequency information due to non-linear imaging terms. We have already used the 3D FT of axial (non-tilted) through-focus images to reduce the effect of non-linear terms on the linear imaging term, and demonstrated the improvement of monochromated lower-voltage TEM performance [Kimoto et al., Ultramicroscopy 121 (2012) 31-39]. Here we apply the 3D FT method with intentionally tilted incidence to normalize various factors associated with a TEM specimen and an imaging device. The temporal partial coherence of two microscopes operated at 30, 60 and 80 kV is evaluated. Our method is applicable to such cases where the non-linear terms become more significant in lower acceleration voltage or aberration-corrected high spatial resolution TEM.
authors.affiliation: National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; Research Acceleration Program, Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan. Electronic address: kimoto.koji@nims.go.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Kimoto
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sawada
authors.forename: Takeo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Yuta
authors.initials: Y
authors.lastname: Sato
authors.forename: Takuro
authors.initials: T
authors.lastname: Nagai
authors.forename: Megumi
authors.initials: M
authors.lastname: Ohwada
authors.forename: Kazu
authors.initials: K
authors.lastname: Suenaga
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ishizuka
mesh_terms: D005583:Fourier Analysis; D021621:Imaging, Three-Dimensional / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*
keywords: High-resolution transmission electron microscopy; Information limit; Spherical aberration corrector