Nobel Prize in physics awarded for work with light

Invention of charge-coupled device, enabling of fiber-optic communication recognized

Three scientists will share the 2009 Nobel Prize in physics for scientific discoveries that revolutionized the fields of telecommunications and photography, the Royal Swedish Academy of Sciences announced October 6.

ELECTRONIC EYE Invention of the charge-coupled device in the late 1960s (an early version of a CCD is seen in this archival image) earned two researchers a share of the 2009 Nobel Prize for physics. Alcatel-Lucent Bell Labs

Half of the prize was awarded to Charles K. Kao, retired director of engineering at the Standard Telecommunication Laboratories in Harlow, England, for research that led to dramatic improvements in fiber-optic telecommunications. The other half will be split equally by Willard S. Boyle and George E. Smith, both retired from Bell Laboratories in Murray Hill, N.J., for inventing the charge-coupled device, a semiconductor circuit that captures images in digital cameras, medical imaging devices and telescopes.

In the late 1960s, fiber-optic communication was a phenomenon known only in the lab because low-quality glass fibers prevented efficient transmission of light. About 99 percent of the light sent down a glass fiber disappeared after traveling only 20 meters. But Kao’s research hinted that chemical impurities in the glass, not physical imperfections, were to blame for the inefficiency. He suggested that light could move more than 100 kilometers through ultrapure glass. Material scientists worldwide rose to the challenge, and within four years researchers at Corning Glass Works in New York had produced a kilometer-long optical fiber suitable for long-distance communication.

Light travels more quickly through glass fibers than electrical signals travel through wires. And laser beams commonly used to encode information can be switched on and off more rapidly than electrical signals. As a result, fiber-optic cables can easily carry several trillion bits of information each second, about 1 million times the data rate possible via radio transmission five decades ago.

“When combined with the laser and the transistor, the invention of an efficient, low-loss optical fiber has made nearly instantaneous communication possible across the entire globe,” says Fred Dylla, director of the American Institute of Physics in College Park, Md.

Such communication is the optical backbone of 21st century commerce, Dylla notes. Today more than 1 billion kilometers of fiber-optic cable — enough to circle the Earth 25,000 times — carry phone calls and Internet traffic worldwide.

At about the same time as Kao’s work, Boyle and Smith were seeking a better form of electronic memory when they invented an indispensable part of modern imaging technology — the charge-coupled device, or CCD. These silicon sensors harness the photoelectric effect — which Albert Einstein explained in a 1905 paper that earned him the Nobel Prize in 1921 — to capture images electronically rather than chemically, as film does. One of the duo’s largest challenges was devising a way to efficiently gather and read out the electrical signal from each CCD picture element, or pixel, in a short period of time.

The first commercially available CCDs, manufactured in the early 1970s, measured a mere 100 pixels by 100 pixels, a far cry from the multimegapixel marvels at the heart of today’s cameras and medical imaging equipment. A typical CCDs is the size of a postage stamp, but the charge-coupled devices found in some large-format cameras can cover half the size of the human palm. Arrays of CCDs in some telescopes can capture images with more than 5 gigapixels.

CCDs have revolutionized photography, especially for astronomers. CCDs can detect radiation in wavelengths from X-ray to infrared and are 1,000 times more sensitive than photographic film, so images can be captured in moments rather than hours. For repeated observations of the same slice of sky, astronomers can more easily compare digital images than ones on film.

Boyle and Smith have been repeatedly honored for inventing the CCD. In 2001, the pair received the Optical Society of America’s Land Medal for their achievement. Five years later, their research earned them the National Academy of Engineering’s Draper Prize, the academy’s highest award.

Fiber-optic communication and the CCD, both of which are the results of decades of hard work and development, are essential to how the world operates today, says Dylla. In the realm of science, for example, astronomers sitting in their offices can monitor real-time signals gathered by a CCD-equipped telescope that is halfway around the world.

“I’m thrilled that these two inventions were chosen for recognition,” Dylla says. “Taken together, these inventions may have had a greater impact on humanity than any others in the last half century.”

Award-winning research is no stranger to Bell Labs, scientific home to 13 researchers who have won or shared in seven different physics Nobels, says Jeong Kim, president of Alcatel-Lucent Bell Labs in Murray Hill. “It’s an exciting day,” he notes. “I’m on cloud nine.”

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