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Total external reflection

About: Total external reflection is a research topic. Over the lifetime, 829 publications have been published within this topic receiving 22213 citations.


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Proceedings ArticleDOI
TL;DR: In this paper, the impact of using soft X-ray multilayer mirrors in future Xray telescopes is discussed, and soft Xray reflectivity tests performed on prototype samples presented.
Abstract: A number of X-ray astronomical missions of near future will make use of hard X-ray optics with broad-band multilayer coatings. However multilayer mirrors can be also useful to enhance the effective area of a given X-ray telescope in the "classical" low energy X-ray band (0.1 - 10 keV), the window where X-ray spectroscopy provides very useful plasma diagnostics) with a consistent gain with respect to usual single-layer reflectors. Multilayers for soft X-rays are based on stacks with constant d-spacing (in order to minimize the loss due to the photoelectric effect). A further gain in reflectivity (however only restricted to the energy range between 0.5 and 4 keV) can be achieved by using a low density material as a first external layer of the film, with the role of reducing the photoelectric absorption effect when the mirror acts in total external reflection regime (Carbon is the most performing material for this specific scope). In this paper the impact of using soft X-ray multilayer mirrors in future X-ray telescopes is discussed, and soft X-ray reflectivity tests performed on prototype samples presented.

37 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of small changes in size and index of refraction on the resonance wavelength of spherical micro-resonators was investigated, and it was shown that changes in the index of the refraction have two effects: these changes affect the phase jump on the surface and the optical path length in the resonator.
Abstract: Wave theory and geometrical optics are used to investigate the effect of small changes in size and index of refraction on the resonance wavelength of spherical microresonators. It is shown that changes in the index of refraction have two effects: These changes affect the phase jump on the surface and the optical path length in the resonator. Under certain conditions the effect of the external or internal index of refraction becomes negligible. The influence of the order number of the resonance modes is investigated. Finally, the results of the theoretical analyses are applied to calculate the effect of temperature on the resonance wavelength.

37 citations

Journal ArticleDOI
TL;DR: The current state of the art in one of the most promising techniques of X-ray spectral analysis, namely, total reflection Xray fluorescence analysis (TXRF), is summarized in this paper.
Abstract: The current state of the art in one of the most promising techniques of X-ray spectral analysis, namely, total reflection X-ray fluorescence analysis (TXRF), is summarized. The underlying physical processes, including reflection, refraction, total external reflection (TER) of X-rays, and formation of standing waves by TER, are considered. The construction and crucial components of a modern energy-dispersive TXRF spectrometer, involving X-ray tubes, monochromators, detectors, and reflectors, are described. Examples of analytical application of TXRF are given. High efficiency of this technique for qualitative and quantitative chemical analysis of liquids and solids of various natures is demonstrated. The main research trends in surface analysis and investigation of surface layers of solids by TXRF are discussed.

36 citations

Patent
28 Aug 2003
TL;DR: In this article, a graded effective refractive index is provided by varying the relative thicknesses of the two materials in the local region of the optical medium, where the thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest.
Abstract: An optical medium has a graded effective refractive index with a high maximum refractive index change. The medium is formed using alternating layers of two or more materials having significantly different refractive indices. The thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest. The effective index of refraction in a local region within the medium depends on the ratio of the average volumes of the two materials in the local region. A graded index of refraction is provided by varying the relative thicknesses of the two materials.

36 citations

Journal Article
TL;DR: Relative reflection measurements from glass-cell areas is comparison with the known glass-medium reflection, can therefore be revealing as far as refraction index, cell-glass distance or cell thickness are concerned.
Abstract: Reflection contrast microscope methods are generally used for studies of those portions of the cell that are turned towards the glass coverslip, to comprehend the structure of the cytoskeleton and the dynamics of cell movement, as well as formation of cell-glass contacts. In incident illumination only reflected light contributes to picture formation. The intensity of which in the case of observation of unstained cells is small because of small refraction differences. To overcome this problem a reflection contrast system was developed by Leitz according to Ploem [49], in which by using contrast preserving measures the reflection becomes prominent in comparison with the lens reflexes. The emerging pictures are a result of interferences of reflections at glass-cell, cell-culture medium and culture medium-cell interfaces. According to Fresnel's equations the reflected intensity depends on the differences of the particular refractive indices and the thickness of the layers, which determine the phase of interfering beams. In idealized systems of thin films the reflected intensity is a measure for their optical constants. Relative reflection measurements from glass-cell areas is comparison with the known glass-medium reflection, can therefore be revealing as far as refraction index, cell-glass distance or cell thickness are concerned. The estimates by Bereiter-Hahn et al. [15] were made in the assumption of vertical illumination neglecting its actual conical shape: the comparison of two Fresnel functions of cytological relevant measurements show - in accordance with Gingell and Todd [24] - that this is only permitted under certain conditions, depending on the required accuracy of the measurements; an incidence angle of about 30 degrees leads to an error of about 10%, an angle of 50 degrees to more than 50%.

36 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
20214
20206
20198
20189
201710