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

Hearing the Quantum Difference
Quantum Physics

Hearing the Quantum Difference

At very low volume, a quantum optical microphone performs better than a classical device, and humans can hear the difference. Read More »

Small Molecules Twirl Freely in a Helium Droplet
Optics

Small Molecules Twirl Freely in a Helium Droplet

A laser nudges deuterium molecules into friction-free motion within a superfluid. Read More »

Vortex Jets Spotted in Superconductors
Materials Science

Vortex Jets Spotted in Superconductors

Researchers have identified and studied vortex jets—streams of swirling electrons—that can form at edge defects in current-carrying superconductors. Read More »

More Articles