Physicists lay the groundwork for cooler, faster computing

Dec 14, 2009

University of Toronto quantum optics researchers Sajeev John and Xun Ma have discovered new behaviours of light within photonic crystals that could lead to faster optical information processing and compact computers that don't overheat.

"We discovered that by sculpting a unique artificial inside a photonic crystal, we can completely control the electronic state of within the vacuum," says Ma, a PhD student under John's supervision and lead author of a study published in a recent issue of . "This discovery can enable photonic computers that are more than a hundred times faster than their electronic counterparts, without heat dissipation issues and other bottlenecks currently faced by electronic computing."

"We designed a vacuum in which light passes through circuit paths that are one one-hundredth of the thickness of a human hair, and whose character changes drastically and abruptly with the wavelength of the light," says John. "A vacuum experienced by light is not completely empty, and can be made even emptier. It's not the traditional understanding of a vacuum."

"In this vacuum, the state of each atom - or quantum dot - can be manipulated with color-coded streams of pulses that sequentially excite and de-excite it in trillionths of a second. These quantum dots can in turn control other streams of optical pulses, enabling optical information processing and computing," says Ma.

The original aim of the investigation was to gain a deeper understanding of optical switching, part of an effort to develop an all-optical micro-transistor that could operate within a photonic chip. This led to the discovery of a new and unexpected dynamic switching mechanism, imposed by the artificial vacuum in a photonic crystal. The research also led to the discovery of corrections to one of the most fundamental equations of known as the Bloch equation.

"This new mechanism enables micrometer scale integrated all-optical transistors to perform logic operations over multiple frequency channels in trillionths of a second at microwatt power levels, which are about one millionth of the power required by a household light bulb," says John. "That this mechanism allows for computing over many wavelengths as opposed to electronic circuits which use only one channel, would significantly surpass the performance of current day electronic transistors."

More information: The results appear in a paper titled "Ultrafast Population Switching of in a Structured Vacuum", published online in the Physical Review Letters on December 3.

Source: University of Toronto (news : web)

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5 / 5 (2) Dec 14, 2009
"at microwatt power levels, which are about one millionth of the power required by a household light bulb."

Wouldn't it be more useful to compare this with the power usage of other types of on-chip transistors? Perhaps is doesn't compare well?
not rated yet Dec 15, 2009
A photonic computer as described in this excellent article would certainly have applications in the aerospace industry, such as providing extra brain-power aboard space solar power satellites--that beam down solar energy from space to Earth as described in the book Sunstroke by David Kagan. The computer's high-speed and low heat generation would be of great value in geosynchronous orbit where the Sun beats down 24/7.
not rated yet Dec 15, 2009
Well, aerospace industry and space exploration in general is not limited by computing power. It could help, but the main area where this research is aimed is down here, on the Earth. Imagine a fast netbook that can last a week on one charge...
5 / 5 (1) Dec 15, 2009

A typical Intel Core 2 Quad will pump out about 65watts which is a relatively great feat consisdering that only 12months before a single core would have been about the same power level. A standard house hold light bulb is 60watts so using this as an example is fine, and to non computer people that don't know the average power of a typical CPU will know a 60watt light bulb.

Whats more fantastic then the microwatt power usage is that it can make state changes at such fast speeds! and then multiply that with the number of channels that it can work on via the diffrent freqency of light.

If this technology was ever fully commericalized it would make a 4GHz uber cpu look like an 8086 cpu of two decades past.
not rated yet Dec 15, 2009
Love to have a super-fast netbook with a week's longevity, ShotmanMaslo, and NASA-ESA could sure use the same photonic computer technology that runs cool in high-heat space environments. Especially for auxiliary computing power aboard power satellites that beam down solar energy to Earth like in David Kagan's Sunstroke. Could be a dual market, once it gets off the ground. so to speak. Thx for your input.

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