Nobel Awarded for Advances in Harnessing Light

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October 7, 2009

By KENNETH CHANG

The mastery of light through technology was the theme of this year’s Nobel Prize in Physics as the Royal Swedish Academy of Sciences honored breakthroughs in fiber optics and digital photography.

Half of the $1.4 million prize went to Charles K. Kao for insights in the mid-1960s about how to get light to travel long distances through glass strands, leading to a revolution in fiber optic cables. The other half of the prize was shared by two researchers at Bell Labs, Willard S. Boyle and George E. Smith, for inventing the semiconductor sensor known as a charge-coupled device, or CCD for short. CCDs now fill digital cameras by the millions.

In recent years, the physics prize has varied between perplexing, esoteric advances at the edges of physics and more comprehensible technology developments. Last year, the academy honored “broken symmetry,” a key but esoteric concept in the description of elementary particles. This year’s prize was more akin to the awards in 2007, which honored a discovery that led to smaller, higher-capacity hard disks in laptops and MP3 devices, and 2000, which honored developments in integrated circuits.

In announcing the winners Tuesday morning, Gunnar Oquist, the academy’s secretary general, said the scientific work honored by this year’s prize “has built the foundation to our modern information society.”

Dr. Boyle, raised by telephone to address a news conference held by the Nobel committee in Stockholm, sounded stunned. “I have not had my morning cup of coffee yet, so I am feeling a little bit not quite with it all,” he said.

The awards ceremony will be held in Stockholm on Dec. 10.

Fiber optic cables and lasers capable of sending pulses of light down them already existed when Dr. Kao started working on fiber optics. But at that time, the light pulses could travel only about 20 meters through the glass fibers before 99 percent of the light had dissipated. His goal was to extend the 20 meters to a kilometer. At the time, many researchers thought tiny imperfections, like holes or cracks in the fibers, were scattering the light.

In January 1966, Dr. Kao, then working at the Standard Telecommunication Laboratories in England, presented his findings. It was not the manufacturing of the fiber that was at fault, but rather that the ingredient for the fiber — the glass — was not pure enough. A purer glass made of fused quartz would be more transparent, allowing the light to pass more easily. In 197o, researchers at Corning Glass Works were able to produce a kilometer-long ultrapure optical fiber.

According to the academy in its prize announcement, the optical cables in use today, if unraveled, would equal a fiber more than a billion kilometers long.

In September 1969, Dr. Boyle and Dr. Smith, working at Bell Labs in Murray Hill, N.J., sketched out an idea on a blackboard in Dr. Boyle’s office. Their idea, originally intended for electronic memory, takes advantage of the photoelectric effect, which was explained by Albert Einstein and won him the Nobel in 1921. When light hits a piece of silicon, it knocks out electrons. The brighter the light, the more electrons are knocked out.

In a CCD, the knocked-out electrons are gathered in small wells, where they are counted — essentially one pixel of an image. The data from an array of CCDs can then be reconstructed as an image. A 10-megapixel camera contains 10 million CCDs.

“We are the ones, I guess, that started this profusion of little small cameras working all over the world,” Dr. Boyle said.

Besides consumer cameras, CCDs also made possible the cosmic panoramas from the Hubble Space Telescope and the Martian postcards taken by NASA’s rovers.

All three of the winning scientists hold American citizenship. Dr. Kao, 75, is also a British citizen, and Dr. Boyle, 85, is also a Canadian citizen. Dr. Smith is 79.