Synopsis

Superconductor optics

Physics 3, s74
In the domain of unusual optical properties, layered superconductors could be viable materials with a negative index of refraction.
V. Golick et al., Phys. Rev. Lett. (2010)

Materials with a negative index of refraction bend and guide a beam of light in unconventional ways—an effect that could be exploited to make perfect lenses. The search for candidate negative-index materials has identified multilayers of high-temperature superconductors as a possibility. Because these materials are anisotropic, the sign of the electrical permittivity (or, more specifically, elements of the permittivity tensor) can change over a certain frequency range, which opens the possibility for negative-index refraction.

Writing in Physical Review Letters, Vladislav Golick and colleagues at Kharkov University in the Ukraine, in collaboration with scientists in the Ukraine, Russia, Japan, and the US, calculate dispersion curves for so-called “surface Josephson-plasma waves” in layered superconductors. They find a branch of these waves above the Josephson plasma frequency, displaying abnormal surface mode behavior. They also identify a window of THz frequencies (above the plasma frequency) where the permittivities switch signs to produce negative-index refraction. At higher frequencies, their model predicts that light incident through a high-index, transparent medium would be completely refracted (no reflection) inside the layered superconductor.

When the superconductor-layer width is below the free path of the surface waves, the refracted waves could be emitted from the edge of the superconductor in the form of a highly collimated beam. With a magnetic field applied parallel to the layers, it should be possible to modulate this channeling effect to make fast switching shutters and mirrors for guiding light. –Saad E. Hebboul


Subject Areas

OpticsSuperconductivity

Related Articles

Optics Bench on a Graphene Flake
Optics

Optics Bench on a Graphene Flake

A nanoscale, graphene-based device takes advantage of the wave nature of electrons and provides a level of control that will be useful for quantum computers. Read More »

A Lower-Pressure Route to Superconductivity
Superconductivity

A Lower-Pressure Route to Superconductivity

A new synthesis technique pushes high-temperature superconducting materials a step closer to ambient pressure. Read More »

Switching the Twist in X Rays with Magnets
Magnetism

Switching the Twist in X Rays with Magnets

Scientists create a pattern of nanomagnets—called an artificial spin ice—that can control the orbital angular momentum of a scattered x-ray beam. Read More »

More Articles