Metamaterials

Source: Wikipedia. Pages: 96. Chapters: Dielectric, Superlens, Metamaterial antennas, Terahertz metamaterials, Metamaterial cloaking, Photonic metamaterials, Negative index metamaterials, Acoustic metamaterials, History of metamaterials, Tunable metamaterials, Split-ring resonator, Transformation optics, Photonic crystal, Theories of cloaking, Nonlinear metamaterials, Chirality, Richard W. Ziolkowski, Victor Veselago, Evanescent wave, Plasmonic metamaterials, Seismic metamaterials, Metamaterials: Physics and Engineering Explorations, Winston E. Kock, Bloch wave - MoM method, Surface plasmon polaritons, Artificial dielectrics, Negative refraction, Metamaterials Handbook, Metamaterial absorber, Acoustic dispersion. Excerpt: A superlens, super lens or perfect lens is a lens which uses metamaterials to go beyond the diffraction limit. The diffraction limit is an inherent limitation in conventional optical devices or lenses. In 2000, a type of lens was proposed, consisting of a metamaterial that compensates for wave decay and reconstructs images in the near field. In addition, both propagating and evanescent waves contribute to the resolution of the image. The first superlens with a negative refractive index provided resolution three times better than the diffraction limit and was demonstrated at microwave frequencies. Subsequently, the first optical superlens (an optical lens which exceeds the diffraction limit) was created and demonstrated, but the lens did not rely on negative refraction. Instead, a thin silver film was used to enhance the evanescent modes through surface plasmon coupling. Two developments in superlens research were reported in 2008. In the first case, alternate layers of silver and magnesium fluoride were deposited on a substrate. Nanoscale grids were then cut into the layers, which resulted in a 3-dimensional composite structure with a negative refractive index in the near-infrared region. In the second case, a metamaterial was formed from silver nanowires which were electrochemically deposited in porous aluminium oxide. The material exhibited negative refraction. In early 2007, a metamaterial with a negative index of refraction for a light wavelength just outside the frequency of the color red was announced. The material had an index of -0.6 at 780 nm. The Binocular microscope is a conventional optical system. Spatial resolution is confined by a diffraction limit that is a little above 200 nanometers. Schematic depictions and images of commonly used metallic nanoprobes that can be used to see a sample in nanometer resolution. Notice that the tips of the three nanoprobes are 100 nanometers.An image of an object can be defined as a tangible or visible representation o