Topic

# Total external reflection

About: Total external reflection is a(n) research topic. Over the lifetime, 829 publication(s) have been published within this topic receiving 22213 citation(s).

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TL;DR: These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.

Abstract: We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials.

7,922 citations

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TL;DR: This experimental verification of negative refraction of electromagnetic waves in a two-dimensional dielectric photonic crystal that has a periodically modulated positive permittivity and a permeability of unity is demonstrated.

Abstract: Materials that can bend light in the opposite direction to normal ('left-handed' materials) reverse the way in which refraction usually works — this negative refractive index is due to simultaneously negative permeability and permittivity1,2,3. Here we demonstrate negative refraction of electromagnetic waves in a two-dimensional dielectric photonic crystal that has a periodically modulated positive permittivity and a permeability of unity4,5,6. This experimental verification of negative refraction is a step towards the realization of a 'superlens' that will be able to focus features smaller than the wavelength of light.

606 citations

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Abstract: A new technique utilizing conventional x‐ray diffraction in conjunction with total external reflection has provided a powerful tool for studying ordered interfaces and surface phenomena. It has been used in this work to study the details of the interface region of a molecular beam epitaxially grown Al single crystal on a molecular beam epitaxially grown GaAs single‐crystal substrate. A simple model including variations of the lattice parameter and disorder in the interface region is in agreement with these experimental results.

479 citations

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Abstract: A method is developed for calculating the scattering of a beam of x rays striking the plane surface of a crystal at an angle below the critical angle for total external reflection The low penetration under this condition offers the possibility of determining the special structure of the surface layers, as has been pointed out by Marra, Eisenberger, and Cho A distorted-wave approach is developed whereby the crystal is first taken to be a homogeneous dielectric slab for the purpose of calculating the distorted wave The distorted wave is considered to illuminate the actual crystal, from which a scattering pattern can then be calculated The effects of absorption can be taken into account; in some cases absorption may offer the possibility of observing near-surface structures at angles of incidence larger than the critical angle Such illumination may also be useful for performing fluorescence analysis of the near-surface layers to determine their impurity content Synchrotron sources offer new opportunities for measurements of these kinds Thermal neutrons may also be used in place of x rays and offer unique opportunities for studying surface magnetization and, through inelastic scattering, surface phonons and, conceivably, surface magnons

406 citations

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TL;DR: It is shown that an electromagnetic (EM) wave undergoes negative refraction at the interface between a positive and negative refractive index material, the latter being a properly chosen photonic crystal.

Abstract: We show that an electromagnetic (EM) wave undergoes negative refraction at the interface between a positive and negative refractive index material, the latter being a properly chosen photonic crystal. Finite-difference time-domain (FDTD) simulations are used to study the time evolution of an EM wave as it hits the interface. The wave is trapped temporarily at the interface, reorganizes, and, after a long time, the wave front moves eventually in the negative direction. This particular example shows how causality and speed of light are not violated in spite of the negative refraction always present in a negative index material.

356 citations