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3 Americans win Nobel in physics

Charles K. Kao, Willard S. Boyle and George E. Smith share the prize for revolutionary technologies that led to fiber-optic networks and modern digital photography.

October 07, 2009|Thomas H. Maugh II

One scientist set the stage for the globe-girdling fiber-optic networks that transmit the bulk of everyday television, telephone and other communications. Two other scientists developed the electronic eye that makes digital photography possible. On Tuesday, all three -- described as "masters of light" -- were awarded the 2009 Nobel Prize in physics.

Charles K. Kao, a naturalized American who did most of his work in Britain and Hong Kong, will share half of the $1.4-million prize for demonstrating that highly purified fibers of glass can carry light waves for long distances. Willard S. Boyle and George E. Smith, also Americans, will share the other half for developing the charge-coupled device, or CCD, which in less than two decades has filled the world with inexpensive digital cameras and camera-equipped cellphones.

The announcement was greeted with acclaim for the impact the men have had on the lives of average people the world over.

Fiber-optic communication "is essential for high-speed Internet and forms the optical backbone of 21st century commerce," said H. Frederick Dylla, executive director of the American Institute of Physics. "The CCD sensor has revolutionized technical, professional and consumer photography in the last few decades. Taken together, these inventions may have had a greater impact on humanity than any others in the last half-century."

For The Record
Los Angeles Times Thursday, October 08, 2009 Home Edition Main News Part A Page 4 National Desk 1 inches; 50 words Type of Material: Correction
Nobel Prize: An article in Wednesday's Section A about the 2009 Nobel Prize in physics included a photo of winner George Smith holding a camera that the caption said used a CCD sensor, for which he won the prize. The camera is a newer-generation model that uses a CMOS sensor.

Humans had known for more than 4,000 years that glass could transmit light, but the process was inefficient. When researchers developed the first optical instruments to look inside mechanical equipment and the human body, they used bundles of glass fibers. These crude devices leaked light from one fiber to surrounding fibers, impairing efficiency and the integrity of images.

That problem was partially solved by the 1940s by coating each fiber with glass of a slightly different refractive index, which reflected light back into the fiber. Nonetheless, after only about 60 feet, most of the light had been lost.

In the late 1960s, Kao, who was then a young scientist at Standard Telecommunications Laboratories in Britain, began studying such fibers with the goal of having 1% of the light remain after a distance of 0.6 miles (one kilometer). Although other scientists thought that transmission losses were caused by imperfections in the crystal structure of the glass, Kao decided that it was caused by fiber impurities absorbing light. He concluded, theoretically, that a highly purified fused quartz glass would be much more efficient.

In 1971, technicians at Corning Glass Works in Corning, N.Y., used his ideas to produce the first long, ultra-thin glass fiber. Today, after further refinements, such fibers retain 95% of light after 0.6 miles, a remarkable achievement. Such fibers, moreover, are strong, lightweight and flexible.

In 1988, the first optical-fiber cable was laid beneath the Atlantic Ocean, capable of carrying tens of thousands of times more information than the metal cables it replaced. Today, more than 600 million miles of optical fiber have been laid.

Boyle and Smith didn't set out to revolutionize photography. As researchers at Bell Laboratories in New Jersey 40 years ago, they were looking for a better memory device for computers. To build one, they took advantage of the photoelectric effect that won Albert Einstein a Nobel in 1921. In short, when light hits a small piece of silicon, it knocks electrons out of their orbits; if the silicon has been formed into small photocells, or pixels, each cell acts as a well that captures and holds the electrons for an extended period.

The men devised a way to read out the number and location of electrons captured in each well in an array of photocells. In a 10-by-10 array, for example, the data are transformed into a chain of electron concentrations 100 pixels long. This can be converted back into information.

Within a year, in 1970, Boyle and Smith had given up on their memory device and produced a digital video camera. Two years later, Fairchild Semiconductor of San Jose constructed a camera with a (small by modern standards) 100-pixel-by-100-pixel photo sensor (10,000 pixels), which entered production a few years later. By 1975, the Bell duo had constructed a digital video camera suitable for television.

In 1986, the first 1.4-megapixel camera was produced. Today, sensors exceeding 100 megapixels are available, and they have uses not only in photography, but also as sensitive detectors in telescopes and other devices.

The development not only made digital cameras ubiquitous, but also provided new ways of processing visual information. Astronomers, for example, can subtract a scan of the sky on one night from that of the next to search for comets and other fleeting phenomena. Artists and others can easily manipulate images.

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