Showing papers on "Total external reflection published in 1996"
TL;DR: In this article, time-dependent extended X-ray absorption fine structure (QEXAFS) measurements using the total external reflection geometry were used for the in situ investigation of the potentiostatic silver oxide formation in 1 M NaOH.
Abstract: Time-dependent extended X-ray absorption fine structure (QEXAFS) measurements using the total external reflection geometry were used for the in situ investigation of the potentiostatic silver oxide formation in 1 M NaOH. It is demonstrated that this EXAFS tool yielding near range order structural information is well suited for time-resolved studies of electrode surfaces under potential control. As examples, the initial growth stages of thin silver(I) oxide layers are presented as well as changes of the near range order of thick Ag2O films induced by potentiostatic transients. A comparison of the experimental results with those of model calculations permits the determination of the reaction kinetics of electrochemical phase formation.
32 citations
Patent•
26 Jul 1996
TL;DR: In this paper, a reflecting plate with an average roughness (Ra) of 200-1500 nm along its center line is fitted to a reflection type liquid crystal display device, and peak reflection occurs at one or two angles of reflection deviated by at least 5 degrees from the regular angle of reflection.
Abstract: A reflecting plate having a reflective surface with an average roughness (Ra) of 200-1500 nm along its center line, on which the distribution of reflection of light incident at a predetermined angle from a light source depends on the angle of reflection, and peak reflection occurs at one or two angles of reflection deviated by at least 5 degrees from the regular angle of reflection. A semitransparent reflecting plate, on which the distribution of reflection of light incident at a predetermined angle from a light source depends on the angle of reflection, and peak reflection occurs at one or two angles of reflection deviated by at least 5 degrees from the regular angle of reflection. When such a reflecting plate is fitted to a reflection type liquid crystal display device, bright and clear images can be viewed without effects of external light.
25 citations
Patent•
28 Jun 1996TL;DR: In this article, a sensor system including a first layer having first and second surfaces and a first index of refraction, a second layer having a second index less than the first index, and a mechanism for generating a first diffuse light beam which passes through the first layer from the first surface to the second surface, and the mechanism for sensing a portion of the first diffused light beam reflected back through the second layer.
Abstract: A sensor system including a first layer having first and second surfaces and a first index of refraction, a second layer having a second index of refraction which is less than the first index of refraction, a mechanism for generating a first diffuse light beam which passes through the first layer from the first surface to the second surface, and a mechanism for sensing a portion of the first diffuse light beam reflected back through the first layer to the first surface as an incident of the first diffuse light beam impinging upon the second layer. Also a method of determining the properties of a medium, the method including the steps of generating a first diffuse light beam, passing the first diffuse light beam through a first surface of a first medium having a first index of refraction, causing a portion of the first diffuse light beam to pass through the first medium, to impinge upon a second medium having a second index of refraction less than the first index of refraction and to reflect back to the first surface, and sensing the portion of the first diffuse light beam reflected back to the first surface.
19 citations
TL;DR: In this paper, a new method has been proposed for determining the atomic number density of a near surface element in materials using its grazing X-ray reflection and anomalous dispersion effect.
Abstract: A new method has been proposed for determining the atomic number density of a near-surface element in materials using its grazing X-ray reflection and anomalous dispersion effect The essential equations for analyzing the measured intensity data and the capability of this anomalous grazing X-ray reflection (AGXR) method have been described by obtaining the atomic number densities of near surface elements in some selected examples of ZrO 2 -Y 2 O 3 crystal, Cr thin film grown on a glass substrate and passivated stainless steel The variation of the critical angles of total external reflection through the anomalous dispersion effect was clearly detected and the results suggest the AGXR method is rather surprisingly works well, although there are differences in detail when compared with the values calculated from the bulk density
12 citations
Patent•
16 Jul 1996
TL;DR: In this paper, a basic reflection surface is formed by preliminarily setting a basic surface on which multiple paraboloids are to be formed, under a setting condition, and if the result of the preliminary setting is good, the setting condition is changed to another or other setting conditions, and the step of preliminary setting and evaluation of the incident angle distribution are repeated under the changed setting condition or conditions.
Abstract: A method of forming a reflection surface of a reflection mirror of a vehicle lamp includes the following steps. A basic reflection surface is formed by preliminarily setting a basic reflection surface on which multiple paraboloids are to be formed, under a setting condition. Angles θ at which light that is emitted from a light source located at a focal point is incident on different positions on the basic reflection surface, are calculated, to thereby form a plural number of contours of equal incident angles on the basic reflection surface. A distribution of incident angles is evaluated on the basis of the contours of equal incident angles. If the result of the evaluation is good, the basic reflection surface is set as a final basic reflection surface. If it is no good, the setting condition is changed to another or other setting conditions, and the step of the preliminary setting and the step of the evaluation of the incident angle distribution are repeated under the changed setting condition or conditions. Through those steps, a basic reflection surface can reliably be set which has an incident angle distribution excellent in suppressing the generation of dark portions on the reflection surface to the minimum and at the same time securing a required solid angle of the reflection mirror.
12 citations
TL;DR: Experimental evidence directly supports the theoretical predictions regarding responses to both the real and imaginary portions of theRefractive index: the reflection coefficient derivative wavelength peak position shifts linearly with changes in the real part of the refractive index, and the derivative peak amplitudes exhibit a square-root dependence on absorbance.
Abstract: An optical sensing technique is described and evaluated for sensitivity to changes in refractive index and absorbance of model sample matrices. A binary dielectric/metal transmission diffraction grating is placed in contact with a sample and utilized in reflection mode; thus, the light captured and analyzed does not pass through the sample. This particular condition creates thresholds at which a particular transmitted diffraction order is transformed from a traveling wave to an evanescent one. The positions of these thresholds depend upon the complex dielectric function of the sample, the period of the grating, and the wavelength and incident angle of light striking the grating. Experimental evidence directly supports the theoretical predictions regarding responses to both the real and imaginary portions of the refractive index: the reflection coefficient derivative wavelength peak position shifts linearly with changes in the real part of the refractive index, and the derivative peak amplitudes exhibit a square-root dependence on absorbance. Refractive index sensitivity to a series of ethanol/water solutions is demonstrated with detectable changes in index as small as 2 × 10(-)(6). Absorbance sensitivity is shown via the differentiation of methylene blue samples having equivalent 1 cm path length absorbances between 0.459 and 244 AU. In a single reflection measurement, GLRS offers a large dynamic range for absorbance detection, allows simultaneous determination of bulk refractive index in optically dense media, and provides a platform for performing continuous process analysis.
10 citations
TL;DR: In this article, the effects of energy dependence of secondary radiation emission (SRE) followed by nuclear resonant and nonresonant photo-absorption at Mossbauer total external reflection (MTER) have been considered theoretically and checked experimentally.
Abstract: The effects of energy dependence of secondary radiation emission (SRE) followed by nuclear resonant and nonresonant photo-absorption at Mossbauer total external reflection (MTER) have been considered theoretically and checked experimentally. Numerical interpretation of a set of MTER and CEM spectra at different grazing angles has given the depth profiles of electronic density, photoabsorption coefficient and hyperfine interaction variations in 50 nm slightly oxidized57Fe film. Empirical functions of photo- and conversion electron yield are also determined. They appeared to be nonsimilar and nonmonotone. The energy dependencies of SRE are recalculated for time domain Mossbauer spectroscopy of synchrotron radiation (SR). The coherent nature of the TER effect reveals itself in the existence of delayed intensity of nonresonant SRE. The relation of nonresonant and resonant SRE, their energy, time and angular spectra strongly depend upon the depth of their creation, which opens a way for depth selective measurements as in the X-ray standing waves method.
10 citations
TL;DR: In this paper, a model describing a moving emitter as a local polarization region which is produced by a light spot from a moving two-dimensional Gaussian beam and scans across a plane dielectric surface is presented.
Abstract: The paper presents a model describing a moving emitter as a local polarization region which is produced by a light spot from a moving two-dimensional Gaussian beam and scans across a plane dielectric surface. The spectral composition, angular spectrum and the refraction, reflection, and polarization properties of such a beam are examined. The amplitude coefficients of refraction and reflection of the moving Gaussian beam are found and its total reflection behaviour and the total polarization angle are examined.
9 citations
TL;DR: In this paper, the influence of smooth (not step-like) variation of the dielectric function near a surface on the reflectivity and scattering of x rays is investigated theoretically with the model function ϵ(z) = 1 − 0.5(1 − ϵ+)(1 + tanh(z/(2L))) taken as an example.
Abstract: The influence of smooth (not step-like) variation of the dielectric function near a surface on the reflectivity and scattering of x rays is investigated theoretically with the model function ϵ(z) = 1 − 0.5(1 − ϵ+)(1 + tanh(z/(2L))) taken as an example. It is shown that the presence of the transition layer can essentially change the shape of the differential scattering intensity diagram, especially when the incidence angle of the x-ray beam is greater than the critical angle of the total external reflection (TER). The results of measurements of the x-ray reflection coefficient and the differential scattered intensity are discussed. The model of the near-surface transition layer is shown to describe quantitatively the specific features of experimental curves for the incident beam beyond the TER region, whereas these experimental data cannot be explained in the framework of a step-like model of the dielectric function, taking into account the scattering from surface roughness.
7 citations
TL;DR: In this paper, four samples with different numbers of Si/Ge-bilayers were grown at the same time by high vacuum vapor deposition onto Si(111)-substrates at room temperature.
Abstract: Four samples with different numbers of Si/Ge-bilayers were grown at the same time by high vacuum vapor deposition onto Si(111)-substrates at room temperature. Diffuse scattering experiments within the region of total external reflection were carried out to investigate the mesoscopic roughness of the interfaces. The data are explained quantitatively using the distorted wave Born approximation (DWBA) for correlated layer systems with self-affine interfaces. Because all samples were grown under identical conditions the interface parameters of the simpler systems were used for the more complex samples in order to reduce the number of free parameters in the refinement. The resulting trends for the roughness amplitude and the in-plane correlation lengths are compared to predictions from different growth models.
6 citations
Patent•
27 Dec 1996TL;DR: In this article, a reconstruction light incidence device is used to set the incidence angle of the reconstruction light to be in the range of plus or minus 92 to 122 degrees, where the first refractive index is more than 0.8 times the size of the second this article.
Abstract: The optical element has a medium with a refractive index (2) which comprises a first refractive index and which has main planes with an end surface. The element also has a holographic film (6) with a second refractive index. This is formed with a predetermined thickness on the main plane of the refractive medium. The element also includes a reconstruction light incidence device (10). This permits reconstruction light to enter into the holographic film (6) from the end surface of the refractive medium at a predetermined angle to the normal of the refractive medium. The reconstruction light incidence device may set the incidence angle of the reconstruction light to be in the range of plus or minus 92 to 122 deg. Preferably the first refractive index is more than 0.8 times the size of the second refractive index of the holographic film (6).
TL;DR: In this article, a model of the molecular order within the domains is developed using 16 in-plane Bragg peaks and their truncation rods measured by X-ray grazing incidence diffraction, and the refined 3D unit cell contains at least four monolayers in a herringbone arrangement of the hydrocarbon chains.
TL;DR: In this article, the effect of interference of nuclear resonant and electronic Rayleigh scattering is theoretically treated in time domain Mossbauer total external reflection, and it is shown that the interference peak observed experimentally on the total delayed reflectivity angular curve is explained by the abrupt increasing of the initial excitation of the resonant sample at the electronic critical angle.
TL;DR: In this paper, the authors measured linear nanometric distances between perfectly smooth plane parallel surfaces by scattering evanescent waves of internally reflected light, where one of the two surfaces is optically disseminative and either possesses a heterogeneous index of refraction or it is capable of absorbing and re emitting radiation.
Abstract: Measurement of linear nanometric distances between perfectly smooth plane parallel surfaces by scattering evanescent waves of internally reflected light is shown to be possible if one of the two surfaces is optically disseminative, that is, it either possesses a heterogeneous index of refraction or it is capable of absorbing and re‐emitting radiation Good agreement was obtained between the nominal 100 nm fly height of a magnetic recording slider and the 92 nm fly height measured by scattered total internal reflection This method is simpler and more informative than interferometry or methods that employ the internally reflected beam
Patent•
19 Jul 1996
TL;DR: In this paper, the authors proposed to set the optical fiber diameter and layout of optical fibers of an optical fiber array so that the accuracy Δn of a refractive index measured on the basis of a total reflexcion critical angle is Δn.
Abstract: PROBLEM TO BE SOLVED: To provide a total reflection type refractive index sensor compact, best suited to measure a refractive index of high temperature liquid and capable of measuring a refractive index with high accuracy. SOLUTION: The emission surface 9 of a wave guide layer and a photo detector 16 are connected by an optical fiber array 12. Totally reflected light from the contact face 8 between a testee M and the wave guide layer is detected by the photodetector 16. It is desirable to set the optical fiber diameter and layout of optical fibers of the optical fiber array 12 so that the accuracy Δn of a refractive index measured on the basis of a total reflexcion critical angle is Δn .
Patent•
04 Mar 1996TL;DR: The volume fraction of voids required to eliminate the Fresnel reflection losses, v 1, is: v 1 = [n 2 -(n m n 2 ) 1/2 ]/[n 2 −n 1 ], where n 2 is the refractive index of the void, n m is the medium surrounding the fiber tip, and v 2 is its volume fraction in the modified surface section as mentioned in this paper.
Abstract: An interface between a surface of a micro optical component, and a second medium of different refractive index can be made substantially non-reflective, thereby eliminating Fresnel reflection losses for a predetermined wavelength at its surfaces, by including micro voids within the component surface. The volume fraction of voids required to eliminate the Fresnel reflection losses, v 1 , is: v 1 =[n 2 -(n m n 2 ) 1/2 ]/[n 2 -n 1 ], where n 1 is the refractive index of the void, n m is the refractive index of the medium surrounding the fiber tip, n 2 is the refractive index of the optical component material, and v 2 is its volume fraction in the modified surface section. The thickness, t, of the layer of lower refractive index material required at the component surface is 2N t cos θ=λ o /2, where λ o is the predetermined wavelength for total cancellation by interference, θ is the angle of incidence, and N=(n m n 2 ) 1/2 , where n 2 , is the refractive index of the component material and n m is the refractive index of the medium in contact with the component surface. At least one dimension of the micro void in the surface plane interfacing the second medium must be not greater than half the predetermined wavelength.
TL;DR: In this article, the authors analyzed the effect of the finite bandwidths of the probe and the driving field on the index of refraction and the gain in a Raman-driven four-level system.
Abstract: We discussed the conditions for realizing maximum index of refraction without absorption of the light and analyzed the effect of the finite bandwidths of the probe and driving field on the index of refraction and the gain in a Raman-driven four-level system. We found that the maximum index of refraction with vanishing absorption can be achieved by changing the intensity of the driving field or changing the detuning between the frequency of the driving field and the resonant atomic transition. The finite bandwidths of the driving field and the probe field could destroy the coherence of atoms, decrease the gain and change the value of the index of refraction
TL;DR: In this article, a method based on total internal reflection is presented for determining the refractive index of materials using a focused light beam and a semicyclindrical lens in contact with materials.
Abstract: A method based on total internal reflection is presented for determining the refractive index of materials. A focused light beam and a semicyclindrical lens in contact with materials are used in the experimental apparatus. The dependence of the internal reflective intensity or reflectivity on the angle of incidence is measured by a photodetector, e.g. linear CCD camera. The critical angle and therefore the refractive index can be obtained from the spacial distribution of internal reflective light. If a monochrometer is chosen as the light source, the chromatic dispersion curve of materials can be determined directly and quickly. The simple method can easily be controlled by computer techniques and applied to both tiny transparent and opaque samples whether they are solid or liquid. The several experimental results have shown that the method is reliable and very useful. It will play a role in many areas relative to the refractive index.
TL;DR: In this article, the effect of total external reflection from an anisotropic crystal in the anomalous dispersion region is calculated for hexagonal BN crystal near the boron K absorption edge.
Abstract: A new method of development of x-ray polaroids is suggested. The idea is based on the effect of total external reflection from an anisotropic crystal in the anomalous-dispersion region. The polarization coefficient for hexagonal BN crystal near the boron K absorption edge is calculated for different glancing angles and thicknesses of sample. It is shown that the method treated provides a simple way of constructing an effective x-ray polaroid.
TL;DR: Using a heater and bolometer as source and detector, the reflection of a pulsed beam of phonons at the free surface of liquid4He has been measured for angles of incidence between 30° and 80° as discussed by the authors.
Abstract: Using a heater and bolometer as source and detector, the reflection of a pulsed beam of phonons at the free surface of liquid4He has been measured for angles of incidence between 30° and 80°. The reflection appears to be specular within the accuracy of the experiment. The reflection coefficient is unity within the experimental error; the weighted mean value is 1.001±0.025.