Feeds

Light goes faster in reverse

Caution: physicists at play

Beginner's guide to SSL certificates

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. ®

Remote control for virtualized desktops

More from The Register

next story
Bond villains lament as Wicked Lasers withdraw death ray
Want to arm that shark? Better get in there quick
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 ...
Renewable energy 'simply WON'T WORK': Top Google engineers
Windmills, solar, tidal - all a 'false hope', say Stanford PhDs
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
prev story

Whitepapers

Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
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.
Driving business with continuous operational intelligence
Introducing an innovative approach offered by ExtraHop for producing continuous operational intelligence.
10 threats to successful enterprise endpoint backup
10 threats to a successful backup including issues with BYOD, slow backups and ineffective security.
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?