Feeds

Light goes faster in reverse

Caution: physicists at play

Intelligent flash storage arrays

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. ®

Intelligent flash storage arrays

More from The Register

next story
Antarctic ice THICKER than first feared – penguin-bot boffins
Robo-sub scans freezing waters, rocks warming models
Your PHONE is slowly KILLING YOU
Doctors find new Digitillnesses - 'text neck' and 'telepressure'
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
Reuse the Force, Luke: SpaceX's Elon Musk reveals X-WING designs
And a floating carrier for recyclable rockets
The next big thing in medical science: POO TRANSPLANTS
Your brother's gonna die, kid, unless we can give him your, well ...
NASA launches new climate model at SC14
75 days of supercomputing later ...
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
I'll be back (and forward): Hollywood's time travel tribulations
Quick, call the Time Cops to sort out this paradox!
prev story

Whitepapers

Designing and building an open ITOA architecture
Learn about a new IT data taxonomy defined by the four data sources of IT visibility: wire, machine, agent, and synthetic data sets.
5 critical considerations for enterprise cloud backup
Key considerations when evaluating cloud backup solutions to ensure adequate protection security and availability of enterprise data.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
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?
Protecting against web application threats using SSL
SSL encryption can protect server‐to‐server communications, client devices, cloud resources, and other endpoints in order to help prevent the risk of data loss and losing customer trust.