Thursday, November 12, 2009

Bending Light and Catching Photons

David Brown of the Washington Post wrote a great article titled:

The article discusses Charles K. Kao, Willard S. Boyle and George E. Smith, who won the 2009 Nobel Prize in Physics for the work they did that led to fiber-optic data transmission and digital photography. 

The article hits on the main point that Kao achieved when it states:
 "While light normally passes through glass and does not go around corners, Kao's work -- aided by that of many other scientists and engineers -- is proof that under the right conditions, those generalities do not hold true. Sometimes light can be kept inside a strand of glass, like water in a pipe.  
It seemed hopeless until Kao and a theoretician colleague, George A. Hockham, made some measurements and calculations. They determined that if the impurities scattering the light rays could be removed from the glass, and if they used a wavelength that the glass molecules could not absorb, then much, much more light would stay inside the fiber."

The other winners, Willard S. Boyle and George E. Smith, in the article  won for their work on Charge-Coupled Devices (CCD).

The article hits on the main point that Willard S. Boyle and George E. Smith achieved when it states:

"In the late 1960s, at Bell Laboratories in New Jersey, they were working on ways to improve memory devices -- a way of storing information acquired over time. The ultimate goal was to eliminate the annoying echo that sometimes occurred in very-long-distance telephone calls. 

They used an array of small squares made from silicon-based semiconductor material. "Semiconductors" are capable of generating an electrical charge, although not as readily as metals and other conductors (hence their name). Electrodes placed nearby can then be used to hold the charges in place and keep them from dispersing. 

Like a row of dominoes of different face value, a line of small semiconductor squares called "pixels" outfitted with electrodes were able to hold a row of different charges. If a voltage was then applied to the array in the right fashion, the charges could be moved off the pixels and "read out." 

After some pondering, they realized that light falling onto the semiconductor chips was being transformed into electrical energy. (Explaining that phenomenon, called the "photoelectric effect," is what won Albert Einstein his own Nobel Prize in Physics in 1921.) With the lab lights off, that interference disappeared.

 "They put two and two together and they realized they had made an imaging device," said J. Anthony Tyson, who was at Bell Labs with the two men and is now a professor of physics at the University California at Davis.

 By combining the photoelectric effect -- light's tendency to kick electrons out of atoms, creating a charge -- and the ability to hold and move an entire array of charges in an organized fashion, they created the basis for digital photography."

The article is a must read because of the tremendous benefit that all of us have seen in our lives from the Internet to digital cameras - to just name a few.

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