Showing papers on "Total external reflection published in 2017"

Refractive index profilometry using the total internally reflected light field.

Abstract: A full-field polarization-based technique is presented for quantitative evaluation of the spatial distribution of the refractive index in macro and micro samples. The sample is mounted on a glass–air interface of a prism, illuminated by a linearly polarized collimated light beam, and two intensity frames are digitally recorded with specific orientations of an analyzer. The pair of intensity data frames captured with this simple setup is combined through an algorithm specially developed for the purpose, to yield the phase difference between the transverse electric and transverse magnetic components of the total internally reflected light field. The phase difference is then related to the refractive index of the sample. Experimental results for refractive index variations in a laser-etched glass plate and red blood corpuscles are presented. One of the salient features of the proposed technique is that the depth of measurement is dependent on the penetration depth of the sample’s evanescent field, which is typically of the order of a few hundred nanometers, thereby facilitating refractive index measurements along a thin section of the sample.

Newton's theory of the atmospheric refraction of light

Abstract: Newton's unpublished theory for the trajectory of a light beam in a medium with varying index of refraction and spherical symmetry is reconstructed. He assumed that light consisted of particles (corpuscles), and derived Snell's refraction law from the assumption that the velocity of these corpuscles is proportional to the index of refraction of the medium, and the acceleration is proportional to its gradient. Surprisingly, Newton's theory leads to a relation for the refraction of light in such a medium that is identically the same as the modern theory based on the wave theory of light.

Total external reflection of X-rays from solid surfaces

Abstract: The reflection of X-rays from solid surfaces is comprehensively studied using the measurements of patterns of total external reflection and X-ray diffraction with the aid of a parabolic mirror. Principles for theoretical processing of X-ray patterns are developed. An inverse dependence of the refractive index of X-ray radiation on the interplanar distances in crystallites is obtained.

Intensification of acoustic beams in crystals at mode conversion near total internal reflection

Abstract: Geometrical conditions under which mode conversion occurs in a crystal near total internal reflection of an acoustic beam are found. In this case, the entire energy of an incident pump wave is spent on the excitation of a narrow intense reflected beam close in structure to an eigenmode. A consistent choice of orientations of the sagittal plane and surface that excludes the reflection of a parasitic wave of leakage is found.

Metasurface-enhanced transparency

Abstract: We consider the problem of light transmission from a high refractive index medium into a low-index environment. While total internal reflection severely limits such transmission in systems with smooth interfaces, diffractive metasurfaces may help out-couple light that enters an interface at blazing angles. We demonstrate that the profile of the structured interface can be numerically optimized to target a specific emission pattern. Our study suggests that while metasurfaces can help to out-couple light from a range of incident directions, there exists a universal limit for total transmission efficiency that depends only on the dielectric properties of the two materials and is independent of the profile and the composition of the metasurface coupler.

Total External Reflection of X Rays from Polycrystal Solid Surface

Abstract: Total external reflection of X rays from surfaces of several polycrystalline metals is analyzed. The roentgenograms of total reflection and X-ray diffraction are comprehensively studied for nickel, copper, silver, platinum, and bismuth. Theoretical processing of experimental roentgenograms is used to calculate Xray refractive indices, number of surface crystallites, interplane distances, and remaining quantities for polycrystalline metals. It is shown that the refractive index inversely depends on the interplane distance in crystallites of polycrystalline solids. Total reflection of X rays from the lead zirconate titanate ferroelectric film is studied.

Anderson localization of light: Strong dependence with incident angle - Supplementary Information

Abstract: This paper studies the transport of light for different incidence angles in a strongly disordered optical medium composed by core-shell nanoparticles (TiO2@Silica) suspended in ethanol solution. A decrease of optical conductance and an increase of absorption near the input border are reported when the incidence angle is increased. We associated this phenomenon to an increase of the density of localized states (localization increase) near the input border, which could be explained by a large increase of internal reflection with the incidence angle, which in turn would be a direct consequence of the enhancement of the effective refractive index near the input border by localization itself. The specular reflection, measured for the photons that enter the sample, is considerably lower than the effective internal reflection undergone by the coherently backscattered photons in the exact opposite direction, indicating a non-reciprocal propagation of light (mirror-symmetry breaking). This study represents a novel approach in order to understand the complex physics involved in a strongly disordered optical medium at the critical regime of approaching localization.

Differential Phase Imaging of Evanescent Wave in Total Internal Reflection for Determining Refractive Index

Abstract: A non-interferometric differential phase measuring technique is used to determine the refractive index of a medium. In total internal reflection (TIR), phase change is a function of the refractive indices of a pair of media involved. Also, the said phase change is different for p-polarized and s-polarized light components. Difference between the phases of these two polarized light components leads to the refractive index of the sample. The theory of the technique is discussed and a simple experimental method is demonstrated to determine the phase difference of the totally internally reflected p and s components.

Total Reflection Investigation with Negative and Near Zero Magnetic Permeability along the Visible Light Range and All Negative Values of Magnetic Permeability along the Blue Light Range with Total Reflection

Abstract: In this study, total reflection through a slab of vacuum and mercury nano-particle is achieved with negative and near zero magnetic permeability. It is shown that this new design of metamaterial act as an excellent reflector which could be used in many applications. This paper also shows that this optical mirror has negative values for magnetic permeability in the blue range of the visible light and total reflection in this range is achieved.

Passage of X-rays through a single monocapillary

Abstract: In the paper an analysis of X-ray passage through a single monocapillary under the regime of an one reflection ispresented. It is shown that a ray approximation does not explain the results obtained experimentally. A qualitative estimation of the phenomenon observed and computer simulation by a wave theory are given.Keywords:X-ray, monocapillary, ray optics, wave optics, capillary optics 1. INTRODUCTION A possibility of X-rays control by the multiple total external reflection into hollow tubes is well-known, however,to use the systems of capillaries packed in a definite order for collecting, controlling and forming X-ray beams wassuggested comparatively recently (a detail analysis was presented in the paper [1]). The recent research results on transmission of X-ray radiation through capillary systems showed that passedradiation distribution behind these systems may present a complex character[2]. Under the specific ratio betweenbeam and system parameters the wave properties may be observed.Studying an X-ray transmission through single monocapillaries discovered that in this case the effects, whichare unusual by the ray optics, are observed[3,4]. In the work presented a theoretical analysis on process of X-ray