Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Emerging Technology from the arXiv

A View from Emerging Technology from the arXiv

Record-Breaking Superlens Smashes Diffraction Limit

The world’s highest-resolution lens opens the door to real-time movies of molecules in action.

  • June 11, 2009

It must be 10 years since John Pendry at Imperial College London dreamt up the idea of superlenses. Until then, physicists had thought that the resolution of all lenses was limited by a phenomenon called the diffraction limit, which holds that you can’t see anything smaller than about half the wavelength of the illuminating light.

That’s true if you look at the propagating component of light waves. But light also records smaller sub-wavelength details in its evanescent components, which do not propagate. At least not usually. What Pendry showed was that evanescent components can propagate in a material with a negative refractive index, and he pointed out that a thin film of silver ought to have just the right properties.

Since then, the race has been on to build superlenses. In 2005, Nicolas Fang at the University of Illinois at Urbana-Champaign created one that could record details as small as one-sixth of a wavelength. That was a significant improvement over the diffraction limit, but why not better?

It turns out that silver films just a few tens of nanometers thick are extremely difficult to make. On this scale, silver tends to clump into islands, like water on plastic, making the film rather irregular. This dramatically reduces the ability of evanescent waves to propagate.

Now Fang and a few buddies, including Stan Williams at HP Labs, in Palo Alto, CA, have worked out how to make thin silver films smooth. The trick is to grow the silver on a layer of germanium, which forces it to form a smooth thin film.

This new lens is a huge improvement. With a record-breaking resolution of one-twelfth of the wavelength of light, it opens up an entirely new area of imaging when extended to the far field, a feat that can be achieved by gluing a corrugated silver surface on top of the superlens, says the team.

And greater resolution should still be possible: the theoretical limit is one-twentieth of a wavelength.

Fang and co conclude with the dramatic prediction that these superlenses should make it possible to film molecules in action in real time with visible light.

That ought to be one impressive movie.

Ref: arxiv.org/abs/0906.1213: Molecular Scale Imaging with a Smooth Superlens

Want to go ad free? No ad blockers needed.

Become an Insider
Already an Insider? Log in.
Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.

    See details+

    Print + Digital Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

    Technology Review PDF magazine archive, including articles, images, and covers dating back to 1899

    10% Discount to MIT Technology Review events and MIT Press

    Ad-free website experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning print magazine, unlimited online access plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    Print Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

  • Insider Online Only {! insider.prices.online !}*

    {! insider.display.menuOptionsLabel !}

    Unlimited online access including articles and video, plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

/3
You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.