Paint-on laser could rescue computer chip industry from 'interconnect bottleneck'

Researchers at the University of Toronto have created a laser that could help save the $200-billion dollar computer chip industry from a looming crisis dubbed the "interconnect bottleneck." But this isn't a laser in the stereotypical sense -- no corded, clunky boxes projecting different coloured lights. In fact, Professor Ted Sargent, of the Edward S. Rogers Sr. Department of Electrical and Computer Engineering, carries a small vial of the paint used to make this laser in his briefcase -- it looks like diluted ink.

Lasers that can produce coherent infrared light in the one to two micrometre wavelength range are essential in telecommunications, biomedical diagnosis and optical sensing. The speed and density of computer chips has risen exponentially over the years, and within 15 to 20 years the industry is expected to reach a point where components can't get any faster. But the interconnect bottleneck -- the point where microchips reach their capacity -- is expected sometime around 2010.

To tackle this problem, Sargent, a Canada Research Chair in Nanotechnology, created the new laser using colloidal quantum dots -- nanometre-sized particles of semiconductor that are suspended in a solvent like the particles in paint. "We've made a laser that can be smeared onto another material," says Sargent. "This is the first paint-on semiconductor laser to produce the invisible colours of light needed to carry information through fiber-optics. The infrared light could, in the future, be used to connect microprocessors on a silicon computer chip." A study describing the laser was published in the April 17 issue of the journal Optics Express.

According to Sjoerd Hoogland, a post-doctoral fellow and the first author of the paper, "this laser could help us to keep feeding the information-hungry Internet generation." The laser's most remarkable feature was its simplicity. "I made the laser by dipping a miniature glass tube in the paint and then drying it with a hairdryer," he said. "Once the right nanoparticles are made, the procedure takes about five minutes."

The microchip industry is looking for components that exist on the scale of transistors and are made of semiconductors, which would produce light when exposed to electrical current. With this development, it could be possible to use the electronics already found on microchips to power a laser that communicates within the chip itself.

"We crystallized precisely the size of the nanoparticles that would tune the colour of light coming from the laser. We chose nanoparticle size, and thus colour, the way a guitarist chooses frets to select the pitch of the instrument," Hoogland said. "Optical data transfer relies on light in the infrared--beams of light 1.5 micrometers in wavelength travel farthest in glass. We made our particles just the right size to generate laser light at exactly this wavelength."

Lionel C. Kimerling, Thomas Lord Professor of Materials Science and director of the Microphotonics Center at the Massachusetts Institute of Technology, reviewed the work. "The wavelength and the thermal budget of the Toronto laser are very appealing for applications in optical interconnects," Kimerling says. "The performance is excellent, particularly the temperature insensitivity of the output wavelength."

Source: University of Toronto

Related stories:

Can we freeze time? Using lasers to film the secret lives of atoms -- frame by frame
Cutting edge laser 'cameras' which can film the super-fast movements of electrons inside materials are the subject of an Imperial College exhibit at the Royal Society Summer Science Exhibition 2008, which opens to the public today (1 July).
Laser fluorescence could find life on Mars
A team of scientists from the United States and the United Kingdom has developed a technique using ultraviolet light to identify organic matter in soils that they say could be used to document the existence of life on Mars.
Trap and zap: Harnessing the power of light to pattern surfaces on the nanoscale
Princeton engineers have invented an affordable technique that uses lasers and plastic beads to create the ultrasmall features that are needed for new generations of microchips.
Study Finds New Properties in Non-Magnetic Materials
A team of Penn State researchers has shown for the first time that the entire class of non-magnetic materials, such as those used in some computer components, could have considerably more uses than scientists had thought. The findings are important because they reveal previously unknown information about the structure of these materials, expanding the number of properties that they potentially could have. A material's properties, such as electrical conductivity and mechanical strength, are what determine its usefulness. The research will be published in the journal Physical Review Letters.
New unifying theory of lasers advanced by physicists
Researchers at Yale and the Institute of Quantum Electronics at ETH Zurich have formulated a theory that, allows scientists to better understand and predict the properties of both conventional and non-conventional lasers, according to a recent article in Science.
The Photonic Beetle: Nature Builds Diamond-Like Crystals For Future Optical Computers
Researchers have been unable to build an ideal “photonic crystal” to manipulate visible light, impeding the dream of ultrafast optical computers. But now, University of Utah chemists have discovered that nature already has designed photonic crystals with the ideal, diamond-like structure: They are found in the shimmering, iridescent green scales of a beetle from Brazil.
A step toward circuits for terahertz computing
University of Utah engineers took an early step toward building superfast computers that run on far-infrared light instead of electricity: They made the equivalent of wires that carried and bent this form of light, also known as terahertz radiation, which is the last unexploited portion of the electromagnetic spectrum.
Soldiers to get 3-D maps in near-real-time
In the near future, soldiers may be using maps that are more akin to long-range but highly accurate security cameras: the maps will enable troops to see both the exterior and interior of buildings, as well as streets and larger areas, as they appeared just minutes ago.

News discussion:

Paint-on laser in Physics news