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.

Effect of fluctuations on the reflectivity near the angle of total internal reflection

Abstract: Wave propagation in the presence of a rough dielectric interface with total internal reflection is studied theoretically using the Kirchhoff approximation. An approximate expression valid when the surface is smooth enough is obtained for the mean intensity of a point source as a function of propagation range and statistical parameters of a surface. It is shown that if the characteristic angle of incidence is close to the angle of total internal reflection, small irregularities of interface can drastically change the reflectivity and, consequently, the signal level far away from the source. As an example, far beyond the horizon propagation of radiowaves in the presence of elevated irregular reflecting layers in the atmosphere is discussed.

Hybrid transmission-reflection grating

Abstract: A hybrid transmission-reflection grating includes an array of essentially parallel principal interfaces, with each principal interface separating a first medium and a second medium. The first medium has a first index of refraction, and the second medium has a second index of refraction. The first medium allows for transmission of quantum- mechanical objects in excess of one percent of an incident number of quantum-mechanical objects. The array of principal interfaces has a spacing distance between adjacent principal interfaces. The first medium has a width in the direction normal to the principal interfaces, the width being less than the spacing distance. Each principal interface has a length such that either (1) the length is greater that the width divided by tan(2tc), wherein tc is an critical angle of total external reflection for the quantum-mechanical objects at the principal interface, or (2) the length is greater that the width divided by tan(2tc), wherein tc is a critical angle defined by 2πsin(tc) σ = λ, with λ being de Broglie wavelength of the quantum-mechanical objects and σ being a roughness of the principal interface.

Reflection and polarization characteristics of circularly polarized light at the surface of a chiral negative refraction medium

Abstract: The reflection and transmission characteristics are analyzed theoretically when circularly polar- ized light is incident upon the surface of a chiral negative refraction medium.Normalized reflected and transmission power curves vs incident angle,and Brewster angle curves vs the chirality parameter are plot- ted.When the incident angle is larger than the critical angles of two eigen waves,the total internal reflection occurs.Due to the negative refraction of one eigenwave in the chiral medium,the polarization state of the reflected waves caused by the incidence of right or left circularly polarized light is very different from that in the common medium.The reflected waves are linearly polarized with different polarization direction when the light is incident at the Brewster angle.

Interface exafs using glancing angles

Abstract: The use of glancing angles t o o btain EXAFS signals from thin interfacial regions is described. The technique is applicable t o the case of a light overlayer on a heavy substrate for which total external reflection can be caused to occur at the interface. In t his case the p enetration into the substrate is very small (520-30 A in many cases). Data have been obtained on two systems: A1 on Cu and Ag on Au. The A1 on Cu samples had 1000 A of A1 on Cu and measurements were made on the interface structure as a function of annealing temperature. For anneals above 140°C clear indication of the growth of CuAIZ at the interface is observed. The interface sensitivity was then verified by varying the glancing angle to determine the CuA12 layer thickness. Even for CuA12 layers as thin as 100 A, the EXAFS signal is essentially pure CuAl2 with little contamination from the underlying Cu. For Ag on Au there is no compound formation and these techniques were used to look at interdiffusion as a function of annealing. In particular the Au environment in Ag grain boundaries could be detected. Understanding the structure of solid state interfaces is important for studies of solid state reactions, t hin film adhesion and stability. Traditional probes such as Auger sputter p rofiling and Rutherford backscattering can provide compositional information but no detailed structural information, and for buried interfaces often have only limited depth resolution. For single crystal interfaces electron microscopy can provide beautiful images, but sample preparation can be tedious and many systems involve polycrystalline or amorphous interfaces. In this paper the applications of glancing angle x-rays to the study of buried interfaces are discussed with particular emphasis on interface extended x-ray absorption fine s tructure (ExAFS) measurements.