補習-華人科學家高錕獲2009諾貝爾物理學獎 |
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左起：高錕、威拉德·博伊爾和喬治·史密斯
Three scientists who harnessed the power of light in ways that turned the Internet into a global phenomenon and launched the digital camera revolution were jointly awarded the Nobel Prize in physics. Charles Kao, who was born in Shanghai, China, and has both U.K. and U.S. citizenships, received half the total prize money of .4 million. Dr. Kao was lauded for a breakthrough that led to fiber-optic cables, the thin glass threads that carry a vast chunk of the world's phone and data traffic. The other half of the prize is shared by Willard Boyle and George Smith of Bell Laboratories in Murray Hill, N.J., for work that led to the charge-coupled device, or CCD. The CCD sensor turns light into electrical signals and eliminates the need for capturing images on film, a far more cumbersome and expensive approach. Drs. Smith and Boyle are American; Dr. Boyle also holds Canadian citizenship. The Nobel committee described the three physicists as masters of light. Optical fibers, developed in the 1950s, had great theoretical potential. Because light has a very high frequency, it can carry a lot more data than microwaves or radio waves, which have much lower frequencies. However, there was a big hurdle: Impurities in the glass fibers of the time absorbed much of the light. For every meter traveled about 20% of the light was lost. In 1966, Dr. Kao, while working at Standard Telephones & Cables Ltd.'s laboratory in Harlow, England, tackled this problem. His insight was that if you could get rid of the impurities, you could transmit light over many kilometers, says Jeff Scheck, who authored a history of fiber optics in 1999. Dr. Kao figured out a way to increase the distance to 100 kilometers. Manufacturing breakthroughs then opened the way for moving signals over far greater distances. The first ultrapure fiber was made just four years later, in 1970. Today, fiber-optic cables make up the circulatory system of the Internet, transporting words, sound and images from one end of the planet to the other in a split second. The Royal Swedish Academy of Sciences estimates that if all the glass fibers around the world were unraveled it would stretch to one billion kilometers. That's enough to encircle the globe more than 25,000 times, and its length is increasing by thousands of kilometers every hour. Drs. Boyle and Smith's work transformed photography. By adopting aspects of the photoelectric effect--the breakthrough for which Albert Einstein won his physics Nobel in 1921--the two scientists designed an image sensor that could gather and read out the signals in a large number of pixels, or image points, very quickly. The vast bulk of the image traffic that courses through the Internet is now made up of digital images. Images captured this way can be far more easily processed, stored and distributed than pictures caught on old-fashioned film. CCD technology is now used in point-and-shoot digital cameras, camcorders, high-definition TV, satellites and medical endoscopes. The technology has transformed modern astronomy, too. The Hubble Space Telescope uses a CCD as its main imaging device. The two technologies are increasingly coming together as well. Most photographs taken today are captured digitally and then transmitted optically, via the Internet and other fiber-optic networks.
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