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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Yoked Photons Break a Light Barrier
3 October 2000 7:00 pm
By exploiting entanglement, the quintessential "spooky" phenomenon in quantum mechanics, physicists have come up with a method for drawing tiny features on a microchip that would be impossible according to the classical theory of light. If it proves practical--always a big "if" where quantum effects are concerned--the technique could enable chip designers to circumvent a physical barrier that has limited etching resolution.
As microcircuitry grows ever finer, chipmakers run smack into the so-called Rayleigh limit. This principle dictates that the smallest feature a light beam can write on a chip is half the wavelength of the light. So manufacturers in search of finer circuits must use ever shorter wavelengths. Short wavelengths, however, are both hard to control and tough on chips.
To smash that barrier, Jonathan Dowling and colleagues at the Jet Propulsion Laboratory in Pasadena, California, imagine "entangling" two photons. When shot at a beam splitter from opposite directions, the photons will always wind up moving in lockstep. Thus yoked, the photons will remain inseparable until they strike a target--in this case, the chip-in-progress. The entangled photons could be made out of red light, say, which has relatively long wavelengths and is easy to work with. But when the two photons hit the target together, their combined energy might equal that of a single ultraviolet photon--a particle with a shorter wavelength. "It acts like UV for all intents and purposes," Dowling says. That should make it possible to etch transistors twice as fine as the Rayleigh limit allows, he adds. The team describes their idea in the 25 September issue of Physical Review Letters.
"Dowling had a very brilliant idea to use this for lithography," says Yan-hua Shih, a physicist at the University of Maryland, Baltimore County, who is trying to put the scheme into effect. Other scientists, however, think it will take more than tinkering to rout Rayleigh. Paul Kwiat, a physicist at Los Alamos National Laboratory in New Mexico, suspects that the difficulty of creating bright beams of entangled light will limit the usefulness of the technique. "But it's good to have people think about these things," he says.