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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/

Nanoelectronics deals with functional electron devices, such as transistors, in the nanoscale range size. As the name implies, nanoelectronics runs on electricity, i.e. the transport of electrons. Another approach to creating faster,smaller and more energy-efficient electronics is to move the field of optical information processing towards the nanoscale.

Optical nanoelectronics will work with light instead of electron transport. Here the usual circuit elements such as inductors, capacitors and resistors could be created in order to operate using infrared or visible light. Using nanotechnology, researchers are able to create structures that could operate on the same or smaller scale as the wavelength of light (the wavelength of visible light is roughly between 400 and 700 nanometers).

Going beyond 'conventional' nanoelectronics, researchers have now proposed a form of optical circuitry in which a network of subwavelength nanoscale metamaterial structures and nanoparticles may provide a mechanism for tailoring, patterning, and manipulating optical electric fields in a subwavelength domain, leading to the possibility of optical information processing at the nanometer scale.

Source: http://www.nanowerk.com/spotlight/spotid=2947.php