Optical manipulation, beam-shaping and scanner-free bright-field and dark-field imaging via multimode optical fibre

2013 ◽  
Author(s):  
Tomáš Čižmár ◽  
Kishan Dholakia
Keyword(s):  
Optical Fibre ◽  
Beam Shaping ◽  
Dark Field ◽  
Optical Manipulation ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Multimode Optical Fibre ◽  
Field Imaging

The Dependence of Sample Thickness on Annular Bright Field Microscopy

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
M.M.G. Latting ◽  
W. Walkosz ◽  
R.F. Klie
Keyword(s):  
Image Quality ◽  
Visual Information ◽  
Specific Property ◽  
Dark Field ◽  
Sample Thickness ◽  
Atomic Resolution ◽  
Imaging Method ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Field Imaging

Annular Bright Field (ABF) is a relatively new method of Scanning Transmission Electron Microscopy (STEM) imaging that is desirable because of its ability to provide additional visual information in terms of showing lightweight atoms, whereas standard dark field imaging does not. In order to better understand the parameters necessary to perfect this method, this research article aimed to study a specific property of this imaging method: the dependence of sample thickness on image quality and atomic resolution. Multislice calculations were utilized to generate atomic potentials that were used to simulate different thicknesses of β-Si3N4. The resulting images were then examined to measure atomic full width at half-maximum (FWHM) in order to have a quantifiable value to support visual selection of the best ABF output image. Comparison of image quality/atomic resolution and FWHM values suggested that as a general trend, as sample thickness increases, atomic resolution and image quality deteriorate, citing Huygens' Principle of Classical Optics via the propagation of spherical electron waves through a vacuum. This study will bring a new awareness to the necessary precision required by researchers' sample preparation during Annular Bright Field imaging to yield the best image of their respective samples.

New imaging modes in STEM

1988 ◽  
Vol 46 ◽  
pp. 648-649
Author(s):  
A.V. Jones
Keyword(s):  
Energy Loss ◽  
Dark Field ◽  
Detector System ◽  
Objective Lens ◽  
Acceptance Angle ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Complex Forms ◽  
Field Imaging

The most often quoted advantage of STEM over conventional TEM is the ability to produce multiple simultaneous images by the use of multiple detector systems. In practice, this postulated advantage has seldom been fully utilised, mainly because of the practical difficulties in designing such detector systems.Most STEMs to date have been constructed as two-channel instruments combining annular dark-field imaging with either filtered bright-freld or inelastic imaging. More complex forms of bright-field detector have been employed1, as have parallel-readout systems for energy-loss spectra but the ability of the spectrometer to produce multiple simultaneous images has not been fully utilised.The basis of the problem lies in the fact that the objective lens and the detector system(s) have in most cases been designed by the manufacturers as separate entities in order to simplify the later addition of user-specific detectors. Since the acceptance angle of even the best spectrometers is relatively small, additional post-specimen lenses [with their attendant aberrations] had to be added in order to make full use of the spectrometer.

Precipitation and dislocation decoration via extrinsic gettering of Co, Au and Pt by misfit dislocations in Si/Si-2%Ge epitaxy

1989 ◽  
Vol 47 ◽  
pp. 578-579
Author(s):  
D. M. Lee
Keyword(s):  
Imaging Techniques ◽  
Preceding Paper ◽  
Dark Field ◽  
Misfit Dislocations ◽  
Temperature Dependent ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Weak Beam ◽  
Sample Structure ◽  
Field Imaging

Previous work on the gettering activity of a well defined array of buried interfacial misfit dislocations (MDs) showed that the amount of nickel gettered by MD is dominated by the strong temperature-dependent solubility. Precipitation occurs on or in the immediate vicinity of MDs due to nucleation enhancement by strain effects. High temperature 〈1000°C〉 diffusion of gold resulted in the planar colony precipitates on two {111} planes associated with stacking fault formation. In this contribution, we discuss our continuing research pertaining to cobalt, gold (at low temperature), and platinum gettering by MDs which involves studying the nature of dislocation decoration and impurity precipitation in the Si/Si-2%Ge epitaxial system.All the samples used in this study have a buried Si-2%Ge epitaxial layer of ∼ 2 μm thickness.Co, Au and Pt were deliberately diffused into the wafer. The details of the sample structure and preparation are described in a preceding paper. Two-beam bright field and weak-beam dark field imaging techniques were performed on cross-section TEM specimens.

Dreidimensional abbildende Elektronenmikroskope I. Prinzip der Geräte / Threedimensionally Imaging Electron Microscopes

1972 ◽  
Vol 27 (6) ◽  
pp. 919-929 ◽  
Author(s):  
W. Hoppe
Keyword(s):  
Dark Field ◽  
Imaging Systems ◽  
Atomic Resolution ◽  
Small Object ◽  
Fourier Space ◽  
Bright Field ◽  
Image Construction ◽  
Dark Field Imaging ◽  
Electron Microscopes ◽  
Field Imaging

Abstract Threedimensionally Imaging Electron Microscopes The principles of new electron optical imaging systems will be described which make possible the threedimensional image construction of a small object. Data of threedimensional Fourier space are collected by the registration of several images using primary beams with different tilting angles. The simplest device of such a type - a magnetic fly's eye system - will lead to spherical aberrrations larger than about 20 mm. It will be shown, that there is a good chance to correct “ring zone segment”-systems to reach atomic resolution with or without image-reconstruction-calculations. Not only microscopes with conventional bright field and dark field imaging but also transmission scanning microscopes can be constructed usind these principles.

scholarly journals Improved Techniques For Imaging Of Three-Dimensional Transparent Specimens In Advanced Darkfield And Interference Contrast Modes

2009 ◽  
Vol 17 (3) ◽  
pp. 20-29
Author(s):  
Jörg Piper
Keyword(s):  
Light Microscopy ◽  
Cell Walls ◽  
Three Dimensional ◽  
Dark Field ◽  
Depth Of Field ◽  
Bright Field ◽  
Dark Field Imaging ◽  
Dark Field Illumination ◽  
Open Position ◽  
Field Imaging

In light microscopy, dark field and interference contrast are widely used for examination of transparent specimens. These methods both suffer from various limitations when photomicrographs have to be taken from fine details, especially in three-dimensional specimens requiring a large depth of field.In common dark field illumination, the condenser either is not equipped with an aperture diaphragm, or an existing condenser diaphragm has to remain in the wide-open position. Thus, the depth of field is lower than in bright field images. Moreover, dark field imaging is associated with marginal blooming, especially in linear structures exhibiting with large differences in phase or density (e.g. cell walls, edges in crystals and other mineralogical material).

Toward Quantitative Annular Dark Field Imaging

2001 ◽  
Vol 7 (S2) ◽  
pp. 188-189
Author(s):  
R.R. Vanfleet
Keyword(s):  
Electron Probe ◽  
Quantitative Information ◽  
Dark Field ◽  
Bright Field ◽  
Image Intensity ◽  
Dark Field Imaging ◽  
Careful Measurement ◽  
Annular Dark Field ◽  
Qualitative Effect ◽  
Field Imaging

Annular Dark Field imaging has the potential to be directly quantifiable. By this I mean that with careful measurement, the absolute image intensity has physical meaning. Unlike Bright Field TEM, the ADF image has no contrast reversals with focus and with the exception of thick specimens there are no contrast reversals with changes in thickness. Thus, image intensity is related to thickness, composition, orientation, and structure of local regions whose size is determined by the electron probe. The ability to extract quantitative information about the specimen from the intensity requires careful collection of the intensity data and a solid understanding of how that intensity will change with thickness, composition, orientation, and structure. The qualitative effect of thickness and composition has been well shown in the literature but more quantitative approaches have been lacking.The simplest models of ADF imaging treat each atom interacting

Detection of a point defect in a silicon single crystal by high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 466-467
Author(s):  
M. Awaji
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Point Defect ◽  
Point Defects ◽  
Noise Level ◽  
Dark Field ◽  
Silicon Single Crystal ◽  
High Resolution Image ◽  
Dark Field Imaging ◽  
Field Imaging

It is necessary to improve the resolution, brightness and signal-to-noise ratio(s/n) for the detection and identification of point defects in crystals. In order to observe point defects, multi-beam dark-field imaging is one of the useful methods. Though this method can improve resolution and brightness compared with dark-field imaging by diffuse scattering, the problem of s/n still exists. In order to improve the exposure time due to the low intensity of the dark-field image and the low resolution, we discuss in this paper the bright-field high-resolution image and the corresponding subtracted image with reference to a changing noise level, and examine the possibility for in-situ observation, identification and detection of the movement of a point defect produced in the early stage of damage process by high energy electron bombardment.The high-resolution image contrast of a silicon single crystal in the [10] orientation containing a triple divacancy cluster is calculated using the Cowley-Moodie dynamical theory and for a changing gaussian noise level. This divacancy model was deduced from experimental results obtained by electron spin resonance. The calculation condition was for the lMeV Berkeley ARM operated at 800KeV.

scholarly journals Noninvasive, in vivo assessment of the cervical microcirculation using incident dark field imaging

2021 ◽  
Vol 135 ◽  
pp. 104145
Author(s):  
Yani P. Latul ◽  
Arnoud W. Kastelein ◽  
Patricia W.T. Beemster ◽  
Nienke E. van Trommel ◽  
Can Ince ◽  
...  
Keyword(s):  
Dark Field ◽  
Dark Field Imaging ◽  
Incident Dark Field Imaging ◽  
Field Imaging ◽  
In Vivo Assessment
Sign in / Sign up

Export Citation Format

Share Document