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Researchers have demonstrated the smallest laser ever, consisting of a nanoparticle just 44 nanometers across. The device is dubbed a "spaser" because it generates a form of radiation called surface plasmons. The technique allows light to be confined in very small spaces, and some physicists believe that spasers could form the basis of future optical computers just as transistors are the basis of today's electronics.

While the best consumer electronics operate at speeds of about 10 gigahertz, Mikhail Noginov, professor of physics in the Center for Materials Research at Norfolk State University in Norfolk, VA, notes that optical devices can operate at hundreds of terahertz. Optical devices are, however, difficult to miniaturize because photons can't be confined to areas much smaller than half their wavelength. But devices that interact with light in the form of surface plasmons can confine it within much tighter spots.

"There's currently a big effort, mostly theoretical, towards designing a new generation of nanoelectronics based on plasmonics," says Noginov. Unlike other previous plasmonic devices, spasers are an active element that can produce and amplify these waves. Noginov co-led the development of the new spaser with Ulrich Wiesner of Cornell University and Vladimir Shalaev and Evgenii Narimanov of Purdue University. The work is described today in the journal Nature.

Source: http://www.technologyreview.com/computing/23249/

Manipulating light in a novel way, researchers at the United States Naval Research Laboratory, in Washington, DC, and the University of Alberta, in Canada, have demonstrated that light can be controlled with magnets in very small, transistor-like devices. Such switches could lead to fast, small, and efficient optical chips for cell phones, and optical communications.

The advance combines insights from two nascent research fields. In plasmonics, researchers are studying ways of guiding light along very thin metal wires to allow faster communication between devices on a chip. The other field, spintronics, involves manipulating a property of electrons called spin; in the past several years, spintronics research has enabled ultradense memory in hard drives. Now the Naval Lab and University of Alberta researchers have shown that by manipulating electron spin using magnetic fields, they can turn off and on light that's being guided through metals.

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Source: http://www.technologyreview.com/Infotech/18874/