Posts Tagged ‘Metamaterial

Vacuum as a hyperbolic metamaterial

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As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as a periodic Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state. Since superconductivity is realized along the axis of magnetic field only, strong anisotropy of the vacuum dielectric tensor is observed. The diagonal components of the tensor are positive in the x and y directions perpendicular to the magnetic field, and negative in the z direction along the field. As a result, vacuum behaves as a hyperbolic metamaterial medium. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Spatial variations of the magnetic field curve this effective spacetime, and may lead to formation of “event horizons”, which are analogous to electromagnetic black holes in hyperbolic metamaterials. We also note that hyperbolic metamaterials behave as diffractionless “perfect lenses”. Since large enough magnetic fields probably had arisen in the course of evolution of early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe…..
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Written by physicsgg

August 16, 2011 at 8:23 am

Posted in Materials Science

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Light propagates as if ‘space is missing’

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Schematics of the zero-index metamaterial contained within a Mach-Zehnder interferometer.

Researchers in the UK and the US have crafted an optical nanostructure that allows light to pass through without accumulating a phase change – as if the medium were completely missing in space. The device could find applications in optoelectronics, they say, for instance as a way of transporting signals without allowing information to become distorted.

Whenever light travels through a medium it experiences a phase-shift, as individual oscillations become out of phase with each other. In certain optics applications, including interferometers, these phase variations can introduce an unwanted dispersion of frequencies. This effect can lead to phase distortions, which ultimately reduce the quality of signals….. Read the rest of this entry »

Written by physicsgg

July 18, 2011 at 2:05 pm