Feeds

Light goes faster in reverse

Caution: physicists at play

Security for virtualized datacentres

A group of US physicists funded by the US Department of Energy have made a material capable of making light travel backwards, at speeds "that appear faster than the speed of light", at the smallest wavelength ever.

The work, led by Costas Soukoulis at Iowa State University, could pave the way for a "perfect lens", and could even have implications for the basic laws of physics. Soukoulis himself says: "Snell's law on the refraction of light is going to be different; a number of other laws will be different."

No natural material is capable of refracting light negatively, so scientists working in this area have to use so-called metamaterials, which can be engineered to have a negative refractive index. Normal materials have positive refractive indices, meaning that light bends to the right of an incident beam. Metamaterials can have a negative index, bending light backwards, to the left of the incident beam.

(Some background on metamaterials here for those who are interested.)

The ultimate goal is to make one that works at visible wavelengths, which would make it possible to build a perfect, flat lens. This is some way off, and in the meantime researchers must learn to build materials capable of refracting light at shorter and shorter wavelengths. So far, the best researchers have been able to manage is microwave or far-infrared radiation.

Soukoulis' material can negatively refract electromagnetic radiation at 1.5 micrometres, or in the near-infrared part of the spectrum. This makes it potentially useful for telecommunications, he says.

"When we have a metamaterial with a negative index of refraction at 1.5 micrometers that can disperse, or separate a wave into spectral components with different wavelengths, we can tune our lasers to play a lot of games with light.

"We can have a wavepacket hit a slab of negative index material, appear on the right-hand side of the material and begin to flow backward before the original pulse enters the negative index medium."

The pulse flowing backward also releases a forward pulse out the end of the medium. Thus, the pulse entering the front of the material appears to move out the back almost instantly.

"In this way, one can argue that that the wave packet travels with velocities much higher than the velocities of light," said Soukoulis. "This is due to the dispersion of the negative index of refraction; there is nothing wrong with Einstein's theory of relativity."

You can have a look at his simulations, which run on Windows Media Player, here. ®

Internet Security Threat Report 2014

More from The Register

next story
SECRET U.S. 'SPACE WARPLANE' set to return from SPY MISSION
Robot minishuttle X-37B returns after almost 2 years in orbit
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
America's super-secret X-37B plane returns to Earth after nearly TWO YEARS aloft
674 days in space for US Air Force's mystery orbital vehicle
'Utter killjoy Reg hacks have NEVER BEEN LAID', writes a fan
'Shuddit, smarty pants!' Some readers reacted badly to our last Doctor Who review ...
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
Hardened Hydrazine the source of Galileo satnav FAIL
Russian aerospace firm's kit fails on 46th mission
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Win a year’s supply of chocolate
There is no techie angle to this competition so we're not going to pretend there is, but everyone loves chocolate so who cares.
Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.