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Showing papers on "Total external reflection published in 2010"


Journal ArticleDOI
TL;DR: In this article, the authors demonstrate that commercially produced synthetic diamond crystals do indeed show an unprecedented reflecting power at normal incidence and millielectronvolt-narrow reflection bandwidths for hard X-rays.
Abstract: Hard-X-ray mirrors usually rely on total external reflection at grazing incidence, owing to the high-penetration and low X-ray reflectivity of most materials. A demonstration of the almost perfect reflectance of hard X-rays from diamond at near-normal incidence could allow the development an entirely new class of X-ray optics. Owing to the depth to which hard X-rays penetrate into most materials, it is commonly accepted that the only way to realize hard-X-ray mirrors with near 100% reflectance is under conditions of total external reflection at grazing incidence to a surface. At angles away from grazing incidence, substantial reflectance of hard X-rays occurs only as a result of constructive interference of the waves scattered from periodically ordered atomic planes in crystals (Bragg diffraction). Theory predicts that even at normal incidence the reflection of X-rays from diamond under the Bragg condition should approach 100%—substantially higher than from any other crystal. Here we demonstrate that commercially produced synthetic diamond crystals do indeed show an unprecedented reflecting power at normal incidence and millielectronvolt-narrow reflection bandwidths for hard X-rays. Bragg diffraction measurements of reflectivity and the energy bandwidth show remarkable agreement with theory. Such properties are valuable to the development of hard-X-ray optics, and could greatly assist the realization of fully coherent X-ray sources, such as X-ray free-electron laser oscillators1,2,3.

103 citations


Patent
01 Dec 2010
TL;DR: Low index layers can be used in optical constructions that have multi-tiered light confinement as discussed by the authors, where a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide.
Abstract: Optical constructions use a low index of refraction layer disposed between a low absorption layer and a high absorption layer to increase confinement of light to the low absorption region of the optical constructions. Low index layers can be used in optical constructions that have multi-tiered light confinement. In these constructions, a first tier of reflection is provided when light is reflected at the surface of a low index optical film which is disposed directly or indirectly on a light guide. A second tier of reflection occurs at the surface of a light redirecting film having appropriately oriented refractive structures.

46 citations


Patent
Paul Kenneth Pickard1
06 Dec 2010
TL;DR: In this paper, the authors proposed to use a high refractive index material (RI≦1.6) to direct a greater portion of the light emitted from a source into the lens toward the transmitting end of the lens.
Abstract: Optical elements having components made from high refractive index materials (RI≦1.6) and lamp assemblies incorporating such elements. Various optical elements, such as total internal reflection lenses, can be fabricated from materials having a higher index of refraction than materials typically used in such elements. The compact optical elements have at least one internal reflection surface that directs radiant energy (e.g., light) from a receiving end to a transmitting end. By using a high refractive index material, a lens can be fabricated that directs a greater portion of the light emitted from a source into the lens toward the transmitting end of the lens. Thus, less of the light spills out of the lens at a surface where emission is not intended, reducing the number of lossy bounces needed to direct the light in a particular direction.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the intensity of light signal transmitted through an optical fiber, whose cladding over a finite length is removed, is used as a sensor of refractive index of liquids, in which the fiber is immersed.
Abstract: The intensity of light signal transmitted through an optical fiber, whose cladding over a finite length is removed, is used as a sensor of refractive index of liquids, in which the fiber is immersed. The transmitted light intensity is measured as a function of liquid refractive index for different lengths of the unclad section of the fiber and at each unclad length its sensitivity to change in refractive index of liquid is monitored. The liquid refractive index studied ranges from below the refractive index of the cladding to above that of the core. A plot of normalized light intensity as a function of liquid refractive index for a short unclad length shows a local maximum at a liquid refractive index equal to the refractive index of the fiber core. This maximum becomes less prominent as length of unclad region increases and finally disappears. These observations are interpreted in terms of frustrated total internal reflection of light rays. Sensitivity to refractive index differential, of the sensor response, increases with increase in refractive index of the liquid pair, below that of the fiber core. In this range of refractive index, we observe a maximum in this sensitivity at an intermediate unclad length of the fiber. When liquid refractive index equals core refractive index, at the rising edge of the local maximum observed in sensors of shorter unclad length, the sensitivity maximum disappears. The sensitivity to refractive index differential diminishes as liquid refractive index exceeds fiber core refractive index. Measurements have been performed with five different unclad sensor lengths and a core diameter of 400 and 800 μm. The results for the two core diameters show similar qualitative features.

20 citations


Journal ArticleDOI
TL;DR: In this paper, the light propagation within an absorbing medium and the reflection and refraction at the interface of two absorbing media are studied, where the effective refractive indices depend on both the complex refractive index of the medium and angle between the unit vectors.
Abstract: The light propagation within an absorbing medium and the reflection and refraction at the interface of two absorbing media are studied. By using the unit vectors denoting the planes of constant field amplitude and constant phase respectively, the light propagation and attenuation are described by the effective refractive indices which depend on both the complex refractive index of the medium and the angle between the unit vectors. With the expression for the light propagation, the corresponding Snell's law and the expression of Fresnel coefficients are obtained, which can be applied to describe the reflection-refraction event at the interface between an arbitrary combination of transparent and absorbing media.

12 citations


Journal ArticleDOI
TL;DR: In this paper, the growth mechanism of a protein monolayer at the air-water interface was investigated using dynamic surface tension, diffuse X-ray scattering and Xray fluorescence techniques.
Abstract: The growth mechanism of a protein monolayer at the air–water interface was investigated using dynamic surface tension, diffuse X-ray scattering and X-ray fluorescence techniques. To ensure the surface sensitivity, the grazing angle was kept smaller than the critical angle of the total external reflection for water. The protein solution was inserted into liquid in a Langmuir trough and the surface was monitored with time-resolved measurements which demonstrate a sequential mechanism involving adsorption and relaxation processes characterized with different time-scales. X-ray measurements provide evidence for sudden time-scale shifts which could not be observed with surface pressure measurements. We propose a mechanism to separate adsorption and relaxation processes by simultaneously measuring surface pressure and X-ray scattering. The X-ray fluorescence technique, which is not sensitive to in-plane structural organisation at the surface, supports the X-ray scattering results.

11 citations


Proceedings ArticleDOI
TL;DR: In this paper, a new x-ray metrology for measuring surface periodic grating of semiconductor device pattern was developed, which is applicable for any materials of device patterns without uncertain empirical parameters.
Abstract: We have developed a new x-ray metrology for measuring surface periodic grating of semiconductor device pattern. X-rays irradiate surface of the device area with a shallow glancing angle, which is close to the critical angle of total external reflection of the surface material. The measured x-ray diffraction pattern is reflected to the average cross-sectional profile of the grating. The pattern made from SiO 2 on Si with100 nm-pitch is analyzed by the present x-ray metrology. The obtained profile, for example, line width, height of the grating and so on are well agreed with that observed by cross-sectional transmission electron microscopy. The wavelength of x-ray that we use is 0.154093 nm and it is enough shorter than the critical length of the grating structure, even when the line width becomes 10 nm or less. Therefore, the resolution of the x-ray metrology will be maintained good enough for the analysis that will be required in the future. In addition, x-ray metrology can be measure the cross-sectional profile with nondestructively due to high-transmissivity of x-rays for the materials. Furthermore, the optical parameter of the materials for x-ray is well established, therefore, x-ray metrology is applicable for any materials of device patterns without uncertain empirical parameters.

10 citations


Patent
16 Jul 2010
TL;DR: In this article, a high efficiency refraction body includes a light source chamber and a main refraction surface opposite to the light source, where the reflected light will be refracted through the first and second refraction surfaces so as to pass a lateral of the body.
Abstract: A high efficiency refraction body includes a light source chamber and a main refraction surface opposite to the light source chamber. A first refraction surface and a second refraction surface for refracting the lights are formed to a peripheral of the high efficiency refraction body. A light source is received to the light source chamber. Lights from the light source will be total reflected because the incident angles of the lights exceed a critical angle of the main refraction surface. The reflected lights will be refracted through the first refraction surface and the second refraction surface so as to pass a lateral of the refraction body. A uniform lateral illumination of the refraction body will correct the poor lateral illumination of LED light devices.

10 citations


Journal ArticleDOI
TL;DR: In this article, a modified double 4f imaging system at the wavelength of 800 nm using picosecond pulses with different pulse energies was used to detect changes in the nonlinear refractive index in ZnSe.

10 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the dynamic behavior of a high power microwave beam propagating through a gaseous medium, which is ionized in the wave field by solving the wave equation, and obtained the reflection index of the produced plasma.
Abstract: The dynamic behavior of a high power microwave beam propagating through a gaseous medium, which is ionized in the wave field is investigated. By solving the wave equation, the reflection index of the produced plasma is obtained. It is shown that the cut off condition is different from that of the steady state approximation. The reflection index is less than unity when the plasma density reaches the critical value estimated in the steady state approximation. So, the wave can still propagate through the plasma. By comparing the reflection indexes in the presence and absence of the time delay of the ionization process at different points of the medium, it is shown that it becomes unity much later in the first case. Therefore, the wave propagation takes much more time and consequently the medium is ionized much more.

9 citations


Patent
25 Mar 2010
TL;DR: In this paper, a multilayer zone forming a redirection section for redirecting and transmitting photons through total internal reflection is defined, with each multi-layer zone including a high index material having a first real refractive index n 1 and a first absorption coefficient β 1, a low index material with a second real refraction index n 2 and a second absorption coefficient α β 2, and a grading zone disposed between the high-index material and the low-indexed material and including a grading layer having a third real refractory index n 3 and a third absorption coefficient
Abstract: An optic device includes a multilayer zone forming a redirection section for redirecting and transmitting photons through total internal reflection, each multilayer zone including a high index material having a first real refractive index n1 and a first absorption coefficient β1, a low index material having a second real refractive index n2 and a second absorption coefficient β2, and a grading zone disposed between the high index material and the low index material and including a grading layer having a third real refractive index n3 and a third absorption coefficient β3, wherein n1>n3>n2.

Journal ArticleDOI
TL;DR: From evaluation of the critical angle of total external reflection in the energy range between 184 and 186eV, it is found an enriched concentration of metallic boron inside the Ru-rich layer at the surface, which is not visible in other energy ranges.
Abstract: Energy dependence of the optical constants of boron carbide in the short period Ru/B4C and Mo/B4C multilayers (MLs) are evaluated from complete reflectivity scans across the boron K edge using the energy-resolved photon-in–photon-out method. Differences between the refractive indices of the B4Cmaterial inside and close to the surface are obtained from the peak profile of the first order ML Bragg peak and the reflection profile near the critical angle of total external reflection close to the surface. Where a Mo/B4C ML with narrow barrier layers appears as a homogeneous ML at all energies, a Ru/B4C ML exhibits another chemical nature of boron at the surface compared to the bulk. From evaluation of the critical angle of total external reflection in the energy range between 184 and 186 eV, we found an enriched concentration of metallic boron inside the Ru-rich layer at the surface, which is not visible in other energy ranges.

Proceedings ArticleDOI
10 Sep 2010
TL;DR: In this paper, it was shown that the contrast of the strongest refection resonances exceeds 500% at moderate heating of reflecting cells, and that the nonlinear structures described here do not have saturation properties in the usual sense.
Abstract: This work is devoted to study of the strong selective reflection of obliquely incident laser beam (inclined geometry) from the interface "glass-rubidium vapour". It is shown that the contrast of the strongest refection resonances exceeds 500% at the moderate heating of reflecting cells. The new nonlinear properties of selective reflection resonances have been investigated - asymmetry of saturation of resonant total internal reflection (TIR) and nonlinear structures that appear under conditions close to resonant TIR. The observed structures can not be associated with well-known sub-Doppler resonances in selective reflection. The nonlinear structures described here do not have saturation properties in usual sense. They exist only in the inclined geometry and in a narrow range of saturating values of the surface power density at the interface. The transformation of the fluctuations of reflected light was also investigated at the optical saturation of selective reflection resonances. For this purpose the intensity of incident light was slightly modulated. The reduction of the corresponding intensity modulation was registered in the reflected light. This reduction of the intensity fluctuations ("classical squeezing") and the relatively high selective reflection coefficient offer good possibilities for the squeezing of quantum fluctuations in the reflected light. In the process of appropriate studies it was found that the reduction (squeezing) of photons (quantum) fluctuations in the reflected light beam is about of 5% in compare with the coherent light.

Journal ArticleDOI
TL;DR: This work studies the anomalous negative refraction when a plane wave is incident from an isotropic medium to a uniaxial absorbing medium and the influence of the anisotropy on the refractive indices and the absorption coefficients in thenegative refraction of these materials.
Abstract: In this work we study the anomalous negative refraction when a plane wave is incident from an isotropic medium to a uniaxial absorbing medium. We study the influence of the anisotropy on the refractive indices and the anisotropy on the absorption coefficients in the negative refraction of these materials. Negative refraction can occur for the ordinary and extraordinary waves for a wide range of values of the angle of incidence. The allowed values of the angle of incidence that lead to negative refraction are analyzed in detail as a function of the orientation of the optic axis and the values of the refractive indices and absorption coefficients.

Journal ArticleDOI
TL;DR: In this paper, the authors considered the effect of tunneling of optical beams through a narrow induced inhomogeneity in a refractive index and showed that part of the signal beam leaks if the channel is narrow.
Abstract: We consider the effect of tunneling of optical beams through a narrow induced inhomogeneity in a refractive index. It is shown that under the condition of total internal reflection from the induced channel, part of the signal beam leaks if the channel is narrow. Dependence of the pump beam width at which the tunneling of half signal power occurs is found as a function of the pump intensity and the angle of beam crossing.

Journal ArticleDOI
TL;DR: In this paper, it was shown that negative refraction brings rays to a focus at distances closer to the boundary than can be attained by conventional refraction, which enables reflection to occur, even in media that are impedance matched.

Journal ArticleDOI
TL;DR: In this article, a multilayer mirror was used as a sample carrier and fluorescence excitation under Bragg reflection condition provided better fluorescence yield and hence improved detection sensitivity for an element.

Journal ArticleDOI
TL;DR: In this article, the authors used the two-dimensional Brusselator model to study reflection and refraction of chemical waves, with boundary conditions of chemical wave, with which occurence of observed phenomena at interface as refraction and reflection can be interpreted.
Abstract: This paper uses the two-dimensional Brusselator model to study reflection and refraction of chemical waves. It presents some boundary conditions of chemical waves, with which occurence of observed phenomena at interface as refraction and reflection of chemical waves can be interpreted. Moreover, the angle of reflection may be calculated by using the boundary conditions. It finds that reflection and refraction of chemical waves can occur simultaneously even if plane wave goes from a medium with higher speed to a medium with lower speed, provided the incident angle is larger than the critical angle.

Journal ArticleDOI
TL;DR: In this paper, a laser beam reflects from a back surface glass mirror and falls on a screen, a pattern of discrete bright spots is created by partial reflection and refraction of the light at the airglass interface and reflection at the mirror surface.
Abstract: When a laser beam reflects from a back surface glass mirror and falls on a screen, a pattern of discrete bright spots is created by partial reflection and refraction of the light at the air‐glass interface and reflection at the mirror surface (Fig. 1). This paper explains how this phenomenon can be used to determine the refractive index and the thickness of the glass with a simple measurement. It is possible to utilize this experiment for geometrical optics labs and moreover it would be a nice practice for Physics Olympians.

Journal ArticleDOI
TL;DR: In this article, a combination of X-ray standing waves in total external reflection combined with Xray reflectivity measurements were employed to determine element-specific atomic density distributions in vertical direction.
Abstract: We present a promising combination of methods to precisely determine the morphology of nanostructures, drawing on the example of monodisperse CoPt 3 nanoparticle films deposited by spin coating and dip coating techniques on functionalized Au substrates. Ex-situ X-ray standing waves in total external reflection combined with X-ray reflectivity measurements were employed to determine element-specific atomic-density distributions in vertical direction.

Posted Content
TL;DR: In this article, a general approach to treat reflection and refraction of light of arbitrary polarization from single axis anisotropic plates is presented, which is accompanied by beam splitting and can create surface waves.
Abstract: We present here a general approach to treat reflection and refraction of light of arbitrary polarization from single axis anisotropic plates. We show that reflection from interface inside the anisotropic medium is accompanied by beam splitting and can create surface waves.

Proceedings ArticleDOI
21 Jun 2010
TL;DR: In this paper, the effect of index of refraction of the material in the transmission of electromagnetic waves was investigated, and it was shown that the transmission through the slab is completely different if the index of the refractive index is a function of frequency.
Abstract: Consider a material slab situated between two half free spaces. An electromagnetic waves is obliquely incident on it. We investigate the effect of index of refraction of the material in the transmission of electromagnetic waves. We study three cases of the material: real positive index of refraction, real negative index of refraction and the refractive index is a function of frequency of the incident waves. We show that the transmission of electromagnetic waves through the slab is indifferent whether the index of refraction is real positive or negative. We also show that the transmission through the slab is completely different if the index of refraction is a function of frequency.

Journal ArticleDOI
TL;DR: In this paper, the design of a miniature experimental cell for spectrometry of the surface layers of different materials and the dry residues of liquids, developed on the base of a planar xray waveguide-resonator, along with experimental data, is presented.
Abstract: Features of total external reflection x-ray fluorescence analysis and certain aspects in the miniaturization of spectrometers are briefly considered. The design of a miniature experimental cell for spectrometry of the surface layers of different materials and the dry residues of liquids, developed on the base of a planar xray waveguide-resonator, along with experimental data, are presented.

Journal ArticleDOI
TL;DR: Total-external-reflection x-ray diffraction is the depth-sensitive technique for evaluating layered structures, including epitaxial heterostructures, ion-doped bulk crystals and several quantum-well structures.
Abstract: Total-external-reflection (TER) x-ray diffraction is the depth-sensitive technique for evaluating layered structures, including epitaxial heterostructures, ion-doped bulk crystals and several quantum-well structures. This technique can control the depth of observation by changing both incident and exit angles of x-rays from the surface. In this review, the principle of the TER technique and measurement apparatus are briefly described, and applications of layered-semiconductor samples evaluated using the TER technique are introduced.

01 Jan 2010
TL;DR: In this paper, a method to measure the refractive index of a solution using two laminar flow streams in a microchannel is presented, which is based on the light refraction when the light beam passes through an interface between two flow streams.
Abstract: This paper reports a method to measure the refractive index of a solution using two laminar flow streams in a microchannel. It is based on the light refraction when the light beam passes through an interface between two flow streams. The relationship between the deflection angle of the light beam and the flow rates is discussed, which can be used to study the incident angle and the interface shape between the two flows. The relationship between the deflection angle of the light beam and the refractive index are theoretically calculated and experimentally demonstrated.

Proceedings ArticleDOI
05 Aug 2010
TL;DR: In this article, a 45°•90°•45° triangular prism is placed with its diagonal face downwards on a convex lens surface of large radius of curvature, and an air film at the tiny contact area is seen blue.
Abstract: During total internal reflection of a beam of light in a denser medium, its electric field penetrates into the rarer medium, up to a distance of the order of wavelength. Thus, if same denser medium is also placed at a gap of the order of wavelength, reflection is partial. In this low‐cost experiment, a 45°‐90°‐45° triangular prism is placed with its diagonal face downwards on a convex lens surface of large radius of curvature. Due to unevenness in the two surfaces, there is an air film at the tiny “contact area”. Its thickness can be finely manipulated by applying pressure at the 90°‐edge of prism. At the right thickness of this air film, contact area is seen blue.

Proceedings ArticleDOI
21 Oct 2010
TL;DR: In this paper, the dispersion relations of one dimension absorptive plasma photonic crystal for both the transverse electric wave case and transverse magnetic wave case were studied and the effective phase index of refraction and effective group index was deduced and computed.
Abstract: Transfer matrix method is used to study the dispersion relations of one dimension absorptive plasma photonic crystal for both the transverse electric wave case and the transverse magnetic wave case. The effective phase index of refraction and effective group index of refraction are deduced and computed. The results show that the collision frequency impact the amplitudes of the absorption photonic band gap structure and the effective phase index of refraction especially in the lower frequency. Also, it will change the value of group index of refraction at the band edges.