Showing papers in "Optik in 1995"

TL;DR: In this article, the spherical aberration correction of a 200kV transmission electron microscope (TEM) with a field-emission gun (FEG) is presented.

TL;DR: In this paper, the authors used random-conical reconstructions of the Escherichia coli ribosome obtained with different defocus settings to explore the use of two methods of contrast transfer function correction.

TL;DR: In this article, two methods, designated as diffractogram-tableau (DT) and beam-tilt/cross-correlation BTXC, respectively, are analyzed.

TL;DR: In this paper, a low voltage SEM with a multipole corrector was used for the correction of spherical and chromatic aberrations, achieving a precision of 30 μm and 200 μm, respectively.

TL;DR: In this paper, an analytic and an iterative method for calculating novel quasiperiodic diffractive optical elements (DOEs) capable to focus the radiation into an optical axis segment are developed.

TL;DR: In this article, the point spread function (PSF) of a slow scan CCD camera equipped with a YAG single crystal scintillator has been determined with high precision by two independent techniques, imaging of a sharp edge and evaluation of noise patterns, yield almost identical results for the PSF.

TL;DR: In this paper, super-resolving filters are described, based on the design of Sieracki and Hansen, for improving axial resolution and their behaviour is investigated using a simple model.

TL;DR: In this article, a three-sector detector is proposed for weak specimens in the scanning transmission electron microscope (STEM) for imaging weak specimens at double the conventional bright field resolution, and a robust method is described by which the complex specimen function can be reconstructed from the images obtained by such a detector configuration.

TL;DR: In this article, the authors present a new method (Fourier-Lorenz-Mie theory FLMT) for the calculation of light scattering of spherical particles in an inhomogeneous field.

TL;DR: In this article, a new approach to Moire deflectometry using phase-shifting technique is described, where phase maps are calculated to reconstruct the surface profile of the tested object.

TL;DR: In this paper, a two-photon scanning fluorescence microscope with deep UV excitation and near UV detection was developed, which consists of the second harmonic (532 nm) of a mode-locked Nd-YAG laser, a pulsed-dye laser (630 nm) with Kiton Red, and a CCD camera with an image intensifier.

TL;DR: In this paper, the super-diffraction limiting propagation of cos beams is demonstrated experimentally and a series of new beams whose divergence and intensity, the both of which are better than Gaussian beams, are reported.

TL;DR: In this paper, the axial electromagnetic field of rotationally symmetric electron lenses is optimized with minimum aberrations for various arrangements and constraints, and the characteristic fundamental behavior of the optimized electromagnetic field is discussed in detail.

TL;DR: In this article, a comparison of methods using approximations and fitting parameters for Mott cross-sections is presented, and it is shown that exact differential crosssections should be preferred.

TL;DR: In this article, a double-resolution imaging of weak phase specimens with quadrant detectors in the scanning transmission electron microscope (STEM) is presented. But the reconstruction method assumes no knowledge of the state of the probe-forming lens.

TL;DR: In this paper, the authors proposed the use of image templates in image algebra to represent the STEM image as a set of templates, which are then used to generate an image in the detector plane.

TL;DR: In this paper, a new digital moire contouring technique is proposed based on the demodulation of the generalised carrier fringe pattern using the spatial carrier phase-stepping algorithm combined with computer-generated mask to extract desired 3D surface contouring information which is encoded in the phase distribution of perturbed projection grating.

TL;DR: In this article, a simple analytical analysis of Gaussian beam propagation through the thermal photo-induced lens is presented to explain some important experimental features (in particular peak-to-valley separation and flat wings of the Z-scan curve) and show that the equations obtained earlier for Kerr-like media are not applicable for liquids with steady state thermal nonlinearity.

TL;DR: Huygens-Fresnel principles and Kirchhoff diffraction integral are revised in this article, and it is much closer to physical practice with some new applications with new applications.

TL;DR: In this paper, the Fraunhofer diffraction pattern of a birefringence grating consists of a series of discrete spots corresponding to diffracted orders whose polarization states depend on the grating profile and on the type of bireringence modulation involved.

TL;DR: In this article, the transformation characteristics of new beam produced by coherent coupling through any axisymmetric optical system that can be described by an ABCD transfer matrix are studied in detail.

TL;DR: In this article, the authors proposed an extended form of the Maxwell's equations which predicts the existence of nontransverse electromagnetic space-charge waves arising from the electric polarization of vacuo, which can match the incident and reflected waves at the vacuum interface.

TL;DR: In this article, a new method was developed for the determination of structure factors from energy filtered diffraction patterns, which shows the covalent bonds in Si. The results are compared to results available in the literature.

TL;DR: In this paper, a double-crystal interferometer with convergent beam electron diffraction (CBED) was proposed and the associated two-dimensional computer simulations of the CBED interference pattern using the many-beam Bloch wave theory were in good agreement with the experimental results.

TL;DR: An automatic demodulation technique for a non-linear carrier fringe pattern is presented in this paper. But the results of practical implementation of the algorithm described with experimental image data files show good agreement with theoretical predictions.

TL;DR: In this paper, the imaging properties of a lens masked by two polarisers, one at the central circular zone and the other at the outer annular zone and followed by a quarter wave plate, placed in such orientation that the beams emerging from these zones are right and left circularly polarised.

TL;DR: In this paper, the cutoff characteristics of parabolically deformed planar waveguides are presented by complex propagation parameters, where the real part of the complex propagation parameter β describes the propagation while the imaginary part gives the power attenuation of the particular mode.

TL;DR: In this article, the output intensity distribution of a two-beam interferometer is fed back to an optically addressable phase-only spatial light modulator in one arm of the inter-ferometer, which gives real-time unambiguous display of the path-difference distribution in the interferer.

TL;DR: In this article, the visibility of a DNA molecule in solution in Fraunhofer in-line electron holography has been investigated experimentally using a coherent electron beam from a field emission gun and frozen-hydrated specimen preparation technique.

TL;DR: In this paper, an approximate optical theorem for extinction in a homogeneous chiral medium is derived, which is exact even when dissipation is ignored, and this theorem becomes exact when the chiral media are necessarily dissipative.