3/2/2005

High-Tech Twine

Novel fibers can sense light

By Lisa Scanlon

Mit materials science researchers have created two flexible fibers that com­bine a semiconductor’s electronic prop­erties with the light-transmitting properties of fiber optics. One of the fibers can detect light, and the other can carry optical and electrical information at the same time without the two interfering with each other. The first fiber could be used for a new computer interface, and the second could be used as a cable to send two different classes of information.

The researchers, led by assistant professor Yoel Fink, PhD ’00, made the light-sensing fibers by creating a cylinder composed of a semiconductor core surrounded by four metal wires, all of which were covered with a polymer sheath. The team then heated the cylinder, which was 30 centimeters long and 20 millimeters in diameter, in a furnace and slowly stretched it into a fiber hundreds of meters long and less than a millimeter thick. The second fiber, which transmits both light and electronic signals, was created using the same process, although the cylinder contained different materials in different arrangements.

Because the fibers are composed of materials with different thermal properties, making them perfectly uniform along their entire length was a particularly stiff challenge. “We failed so many times,” says Mehmet Bayindir, a postdoc in the Research Laboratory of Electronics and the lead author of a recent paper in Nature about the technology.

Now that the researchers have perfected the production process, Bayindir says, the fibers could be used to replace the mouse as a computer interface. Someday, people may interact with computers by pointing beams of light at their screens. Fink and his colleagues are now creating hundreds of meters of the fibers in their lab and exploring other possible applications for them.