Katrin Schultheiss

New electrostatic phase plate for phase-contrast transmission electron microscopy and its application for wave-function reconstruction.

A promising novel type of electrostatic phase plate for transmission electron microscopy (TEM) is presented. The phase plate consists of a single microcoaxial cable-like rod with its electrode exposed to the undiffracted electrons. The emerging field is used to shift the phase of the undiffracted electrons with respect to diffracted electrons. The design overcomes the drawback of the spatial frequency-blocking ring electrode of the Boersch phase plate. First, experimental phase-contrast images are presented for PbSe and Pt nanoparticles with clearly varying phase contrast, which depends on the applied voltage and resulting phase shift of the unscattered electrons. With the new phase-plate design, we show for the first time the reconstruction of an object wave function based on a series of only three experimental phase-contrast TEM images obtained with an electrostatic phase plate.

Object wave reconstruction by phase-plate transmission electron microscopy

A method is described for the reconstruction of the amplitude and phase of the object exit wave function by phase-plate transmission electron microscopy. The proposed method can be considered as in-line holography and requires three images, taken with different phase shifts between undiffracted and diffracted electrons induced by a suitable phase-shifting device. The proposed method is applicable for arbitrary object exit wave functions and non-linear image formation. Verification of the method is performed for examples of a simulated crystalline object wave function and a wave function acquired with off-axis holography. The impact of noise on the reconstruction of the wave function is investigated.

New Electrostatic Phase Plate for Transmission Electron Microscopy and its Application for Wave-Function Reconstruction

Achieving phase contrast in transmission electron microscopy (TEM) for weak-phase objects by physical phase plates has recently been an intensively studied topic. Phase plates positioned in the back focal plane (BFP) of the objective lens are used to achieve a relative phase shift of the scattered electrons with respect to the transmitted beam. Two main concepts exist: thin-film phase plates [1,2] and electrostatic phase plates like the Boersch-phase plate [3] with the possibility to adjust the phase shift by varying the applied voltage.

Object-wave reconstruction by carbon film-based Zernike- and Hilbert-phase plate microscopy: A theoretical study not restricted to weak-phase objects

Transmission electron microscopy phase-contrast images taken by amorphous carbon film-based phase plates are affected by the scattering of electrons within the carbon film causing a modification of the image-wave function. Moreover, image artefacts are produced by non-centrosymmetric phase plate designs such as the Hilbert-phase plate. Various methods are presented to correct phase-contrast images with respect to the scattering of electrons and image artefacts induced by phase plates. The proposed techniques are not restricted to weak-phase objects and linear image formation. Phase-contrast images corrected by the presented methods correspond to those taken by an ideal centrosymmetric, matter-free phase plate and are suitable for object-wave reconstruction.

Wave-function Reconstruction by Phase-plate Transmission Electron Microscopy

A method is described for the reconstruction of the amplitude and phase of the object exit wave function by phase-plate transmission electron microscopy. The proposed method can be considered as in-line holography and requires three images, taken with different phase shifts between undiffracted and diffracted electrons induced by a suitable phase-shifting device. The proposed method is applicable for arbitrary object exit wave functions and non-linear image formation. Verification of the method is performed for examples of a simulated crystalline object wave function and a wave function acquired with off-axis holography. The impact of noise on the reconstruction of the wave function is investigated.

Optimal Imaging Parameters in Cs-Corrected Transmission Electron Microscopy with a Physical Phase Plate

The double-hexapole Cs-corrector [1] has substantially improved resolution and interpretability of images in transmission electron microscopy. The device allows the adjustment of arbitrary, even negative Cs-values with a precision of ∼ 1 µm. Lentzen et al. [2] derived optimum imaging parameters \( C_{S,Len} = {\raise0.5ex\hbox{

Method for the production of a multilayer electrostatic lens array

\scriptstyle {64}

Method For The Production Of Multiplayer Electrostatic Lens Array

} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{

Verfahren zum Herstellen einer mehrschichtigen elektrostatischen Linsenanordnung

\scriptstyle {27}

The Way to an Ideal Matter-free Zernike and Hilbert TEM Phase Plate: Anamorphotic Design and First Experimental Verification in Isotropic Optics

}}(\lambda ^{ - 3} u._{\inf }^{ - 4} ) \) and \( Z_{Len} = - {\raise0.5ex\hbox{