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.

Negative Refraction of Chiral Metamaterial Based on Four Crank Resonators

Abstract: Here we present the experimental characterization of a new material constituted by an array of four same handedness three-dimensional cranks impressed on a dielectric substrate. Using a free-wave experimental set up, the transmission and reflection coefficients were measured, and effective values for the refractive index, permittivity and permeability, and chirality parameter were calculated. The material exhibits a high electromagnetic activity and relatively low refractive index; the joined effect of both factors results into negative values for the refraction index for one of the two circular eigenmodes in a 0.4 GHz bandwidth above the resonance frequency.

The Effect of Optical Polarization on Reflection Spectra

Abstract: The theoretical basis for polarization effects in reflection spectra are reviewed. It is shown that light polarized parallel to the plane of incidence interacts more strongly with the absorbing species than does light of perpendicular polarization except under conditions of internal reflection when the absorber is a thin film between two nonabsorbing media. In this instance the relative degree of interaction is determined by the refractive indices of the three phases. Experimental results are presented which show the predicted effects for internal reflection spectroscopy both when the absorbing medium is a solution of (CH3)4NCl in D2O and when it is a monolayer of stearic acid.

Reflection and negative refraction of left-handed metamaterials at microwave frequencies

Abstract: We experimentally investigated the microwave reflection of the negative permeability material composed of periodical arrays of the copper split-ring resonators (SRRs).The negative dielectric materials are composed of periodical arrays of copper wires and left-handed materials(LHMs) in a planar slab waveguide, and the microwave is incident to the surface in different directions.We also investigated the negative refraction through a prism fabricated from the LHMs.The experimental results show that for the negative permeability materials,there is a reflection peak at the resonance frequencies of the SRRs, and the reflectivity of the negative dielectric material is closed to 0dB.A single smaller reflection peak occurs in the reflected curve of the LHMs,the reflectivity of which increases with the incident direction,that is,the reflection increases.The reflection peak has a shift with respect to the transmission peak. It is demonstrated that negative refractive index of -0.796 occurs in the LHMs at the frequency o 800MHz.

Apparatus and method for making and using high index of refraction materials

Abstract: Method and apparatus for increasing the index of refraction, n, by several orders of magnitude. Pumping and probing radiation excite the various atomic levels of a material, and establish coherence between such levels. Index of refraction can thereby be increased while, concomitantly, absorbence of the material is minimized.

Evolution of short-range order in chemically and physically grown thin film bilayer structures for electronic applications

Abstract: Functional thin films are commonly integrated in electronic devices as part of a multi-layer architecture. Metal/oxide/metal structures e.g. in resistive switching memory and piezoelectric microelectrochemical devices are relevant applications. The films are mostly fabricated from the vapour phase or by solution deposition. Processing conditions with a limited thermal budget typically yield nanocrystalline or amorphous layers. For these aperiodic materials, the structure is described in terms of the local atomic order on the length scale of a few chemical bonds up to several nanometres. Previous structural studies of the short-range order in thin films have addressed the simple case of single coatings on amorphous substrates. By contrast, this work demonstrates how to probe the local structure of two stacked functional layers by means of grazing incidence total X-ray scattering and pair distribution function (PDF) analysis. The key to separating the contributions of the individual thin films is the variation of the incidence angle below the critical angle of total external reflection, In this way, structural information was obtained for functional oxides on textured electrodes, i.e. PbZr0.53O0.47O3 on Pt[111] and HfO2 on TiN, as well as HfO2-TiOx bilayers. For these systems, the transformations from disordered phases into periodic structures via thermal teatment are described. These examples highlight the opportunity to develop a detailed understanding of structural evolution during the fabrication of real thin film devices using the PDF technique.