Feeds

Boffins pave the way for DNA photography

Metamaterials make super lenses

Seven Steps to Software Security

Scientists working in the US have developed a lens that could one day allow people to take optical pictures of things as small as a molecule of DNA.

Two groups have come up with different solutions to a problem that was first posed in 2000. Each has built a so called "magnifying super lens" using metamaterials, that is materials that have been carefully constructed on a nanoscale by a person.

Unlike any naturally occurring material, a metamaterial can have a negative refractive index, bending light in the opposite way from a normal ground glass lens. It is this characteristic that might allow optical pictures of the utterly tiny.

The size of an object that a glass lens can image is set by the diffraction limit - the minimum angular separation of two light sources that can be resolved by the lens. In practical terms, this means it is hard for a lens to resolve anything smaller than the wavelength of light being used to create the image.

The super lens goes beyond this point by gathering what are known as "evanescent waves". These are quickly decaying light waves that normal lenses can't capture.

In 2000, Imperial College's John Pendry proposed that their decay could be offset using a material with a negative refractive index. Such a material, he suggested, would allow the evanescent waves to be amplified and turned into normal propagating waves that could be captured by a microscope.

While several metamaterials have been developed since 2000 that can transmit these waves, until now none has been able to take the final step of converting them into propagating waves.

This final piece of the puzzle has been found independently, and using slightly different techniques, by two groups of researchers.

Nature.com reports that one group, from the University of Maryland, has built a flat lens using concentric polymer rings deposited onto a thin film of gold. The team has used it to take a picture of a series of 70nm dots etched into the inner ring.

The other, from the University of California, Berkeley, has constructed a three dimensional stack of silver and aluminium oxide on a quartz substrate. Again, the team has taken a picture of something built into the lens: the word ON was etched into the lens and imaged at a resolution of 130nm.

Both techniques have been published in the journal Science (reference 315 1699, and 315 1686, respectively).

There is, however, a trade off: to gain the increased focus, the lenses sacrifice vast amounts of field depth. According to Igor Smolyanivov from the University of Maryland, this means the biggest problem researchers will have is finding the sample to take a picture of it.

He told PhysicsWeb: "You won't be able to see it if it's out of focus." ®

The Power of One eBook: Top reasons to choose HP BladeSystem

More from The Register

next story
Bad back? Show some spine and stop popping paracetamol
Study finds common pain-killer doesn't reduce pain or shorten recovery
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
World Solar Challenge contender claims new speed record
One charge sees Sunswift travel 500kms at over 100 km/h
SMELL YOU LATER, LOSERS – Dumbo tells rats, dogs... humans
Junk in the trunk? That's what people have
All those new '5G standards'? Here's the science they rely on
Radio professor tells us how wireless will get faster in the real world
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.