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Engineers produce lens that overcomes diffraction limits

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Geplaatst op 12 januari 2012 - 10:44

Engineers produce lens that overcomes diffraction limits

A superlens would let you see a virus in a drop of blood and open the door to better and cheaper electronics. It might, says Durdu Guney, make ultra-high-resolution microscopes as commonplace as cameras in our cell phones.

No one has yet made a superlens, also known as a perfect lens, though people are trying. Optical lenses are limited by the nature of light, the so-called diffraction limit, so even the best wonít usually let us see objects smaller than 200 nanometers across, about the size of the smallest bacterium. Scanning electron microscopes can capture objects that are much smaller, about a nanometer wide, but they are expensive, heavy, and, at the size of a large desk, not very portable.

To build a superlens, you need metamaterials: artificial materials with properties not seen in nature. Scientists are beginning to fabricate metamaterials in their quest to make real seemingly magical phenomena like invisibility cloaks, quantum levitationóand superlenses.

Now Guney, an assistant professor of electrical and computer engineering at Michigan Technological University, has taken a major step toward creating superlens that could use visible light to see objects as small as 100 nanometers across.

The secret lies in plasmons, charge oscillations near the surface of thin metal films that combine with special nanostructures. When excited by an electromagnetic field, they gather light waves from an object and refract it in a way not seen in nature called negative refraction. This lets the lens overcomes the diffraction limit. And, in the case of Guneyís model, it could allow us to see objects smaller than 1/1,000th the width of a human hai....

Lees verder: http://www.mtu.edu/n...story60318.html

Bron: Michigen Tech University

Artikel: http://prb.aps.org/a...v84/i19/e195465

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