A Microscope that Sees without Looking

Nov 21, 2005

A new type of microscope overcomes some of the limitations of optical imaging techniques by looking at how samples affect a tiny antenna, rather than looking at the sample itself.

Most optical microscopes create images by collecting photons reflected from a surface. But when samples get very small or have tiny features, the limitations of optics kick in and prevent the imaging of objects smaller than a micron or so across.

Instead of shining a light on a sample, a team of Swiss and German researchers have found that they can take pictures of a small sample by illuminating a tiny, gold antenna placed near a surface. The antenna emits different signals depending on the sample structure. It's much like sweeping a metal detector over the ground to map out the location of a buried pipe – the rising and falling pitch of the metal detector results because the hidden metal changes the way the detector circuit reacts.

Conventional optical microscopy, on the other hand, is more like radar, which would locate a buried pipe by bouncing radio waves off of it. The microscope in the new study consists of an antenna made from a single particle of gold, 100 nanometers in diameter or smaller, mounted on the tip of a glass fiber that is scanned over the sample at a height of 5 to 10 nanometers.

The system provides detail of structures as small as a few hundred nanometers across, but the researchers believe the technique has the potential to be refined to image features a hundred times smaller.

Original work:

Optical Microscopy via Spectral Modifications of a Nanoantenna
T. Kalkbrenner et al.
Physical Review Letters 95, 200801 (2005)
link.aps.org/abstract/PRL/v95/e200801

Source: American Physical Society

Explore further: Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications

add to favorites email to friend print save as pdf

Related Stories

Local model better describes lunar gravity

29 minutes ago

Two satellites orbiting the Moon as a part of NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission have been mapping its inner structure by measuring subtle shifts in the pull of gravity on the ...

Hackerspaces used to turn ideas turn into reality

1 hour ago

At HeatSync Labs, the tables are littered with computer chips, pens, pads and tools while the room is abuzz with the chatter of would-be inventors hoping to change the world—or just make cool things. They are part of a ...

China Telecom profit rises as mobile data grows

2 hours ago

China Telecom Ltd., one of the country's three main state-owned carriers, said Wednesday its profit rose 11.8 percent in the first half of the year as its Internet and mobile data businesses grew.

Biotech firm's GM mosquitoes to fight dengue in Brazil

2 hours ago

It's a dry winter day in southeast Brazil, but a steamy tropical summer reigns inside the labs at Oxitec, where workers are making an unusual product: genetically modified mosquitoes to fight dengue fever.

Recommended for you

What time is it in the universe?

Aug 29, 2014

Flavor Flav knows what time it is. At least he does for Flavor Flav. Even with all his moving and accelerating, with the planet, the solar system, getting on planes, taking elevators, and perhaps even some ...

Breakthrough in light sources for new quantum technology

Aug 29, 2014

One of the most promising technologies for future quantum circuits are photonic circuits, i.e. circuits based on light (photons) instead of electrons (electronic circuits). First, it is necessary to create ...

User comments : 0