Monday, 17. August 2009, 08:45:57
spaser, plasmonics, nanoelectronics, computers
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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/
Monday, 13. July 2009, 06:47:39
laser, transistor, Computer, chip technology
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An optical transistor that uses one laser beam to control another could form the heart of a future generation of ultrafast light-based computers, say Swiss researchers.
Conventional computers are based on transistors, which allow one electrode to control the current moving through the device and are combined to form logic gates and processors. The new component achieves the same thing, but for laser beams, not electric currents.
A green laser beam is used to control the power of an orange laser beam passing through the device.
This offers another possible route to light-based rather than electronic, computing. Such "photonic" computing is desirable because components using optical fibres carrying light could be much faster than those using wires to carry electricity.
Source:
http://www.newscientist.com/article/dn17400-laser-light-switch-could-leave-transistors-in-the-shade.html
Tuesday, 21. April 2009, 08:11:54
laser, nuclear, energy, fusion
Lasers have usually represented weapons of mass destruction in movies such as "Star Wars," but a newly completed facility has begun harnessing lasers to create a fusion reaction rivaling the power of a miniature sun.
The National Ignition Facility has already test-fired all 192 giant lasers at Lawrence Livermore National Laboratory in California as part of this effort. The lasers will eventually focus their power on compressing and heating a single, pea-sized fuel capsule to more than 180 million degrees Fahrenheit in order to trigger thermonuclear fusion.
"One of the major activities of the NIF is to explore the basics of fusion energy, building a miniature sun on Earth that could supply limitless, safe and carbon-free energy," said Ed Moses, National Ignition Facility (NIF) program director.
Source:
http://www.livescience.com/space/090408-tw-laser-fusion.html
Tuesday, 10. February 2009, 09:21:51
laser, communications, electro-optics, optics
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Sliced light is how we communicate now. Millions of phone calls and cable television shows per second are dispatched through fibers in the form of digital zeros and ones formed by chopping laser pulses into bits. This slicing and dicing is generally done with an electro-optic modulator, a device for allowing an electric signal to switch a laser beam on and off at high speeds (the equivalent of putting your hand in front of a flashlight). Reading that fast data stream with a compact and reliable receiver is another matter.
A new error-free speed-reading record using a compact ultra-fast component—640 Gbits/second (Gbps, or billion bits per second)—has now been established by a collaboration of scientists from Denmark and Australia, who report their results in the journal Optics Express, the Optical Society's (OSA) open-access journal.
Source:
http://www.eurekalert.org/pub_releases/2009-02/osoa-dtt020209.php
Wednesday, 6. August 2008, 07:50:50
laser, semiconductor, communications, photonics
Applied scientists at Harvard University in collaboration with researchers from Hamamatsu Photonics in Hamamatsu City, Japan, have demonstrated, for the first time, highly directional semiconductor lasers with a much smaller beam divergence than conventional ones. The innovation opens the door to a wide range of applications in photonics and communications. Harvard University has also filed a broad patent on the invention.
"Our innovation is applicable to edge-emitting as well as surface-emitting semiconductor lasers operating at any wavelength—all the way from visible to telecom ones and beyond," said Capasso. "It is an important first step towards beam engineering of lasers with unprecedented flexibility, tailored for specific applications. In the future, we envision being able to achieve total control of the spatial emission pattern of semiconductor lasers such as a fully collimated beam, small divergence beams in multiple directions, and beams that can be steered over a wide angle."
Source:
http://www.eurekalert.org/pub_releases/2008-07/hu-sdh072208.php
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