By Avi Machlis
Small Times Correspondent

JERUSALEM, March 1, 2002 –Israeli scientists have found a way to use nanocrystals to turn polymers, or plastics, into devices capable of conducting optical telecommunications, a breakthrough that could pave the way to a new breed of optical components.

The discovery, reported in the latest issue of Science magazine, was made by Professor Uri Banin, a director of the nanotechnology center at the Hebrew University of Jerusalem, and Nir Tessler, from the electrical engineering department at the Technion-Israel Institute of Technology. Although the researchers admit practical


Illustration courtesy of Nir Tessler and Uri Banin
A breakthrough in nanomaterials for optical components
could enable information to stream to homes at unprecedented
rates directly to the end users via fast fiber-optic connections.

applications are far off, optics industry experts say the discovery is important because materials for optical communications have been limited to a small pool of specific inorganic semiconductors.

In recent years, plastics have been used to create light emitting diodes (LEDs) that emit visible light for a variety of products. But material scientists were not able to get them to work the range of 1.3 microns or 1.5 microns, the near infrared wavelengths used for optical telecommunications.

“We found a way to extend the optical activity to that range by combining nanocrystals with conjugated polymers,” said Banin. “What we have made is a prototype for a very rudimentary device. It provides alternative means of making electronics.”

Banin said that commercial applications for the patent-pending prototype are not around the corner. However, as the optics industry moves toward delivering high-speed data links to households, he believes applications will emerge for cheap devices needed for achieving optimal data transmission speeds in home electronics.

The technology, a device that measures about 100 nanometers thick and uses nanocrystals of indium arsenite, still needs to be improved. Its efficiency — the number of photons emitted divided by the number of electrons entering — only reaches 2 to 3 percent. This is still better than previous polymer-optics attempts, which yielded efficiency of 0.01 percent, but not enough for commercial applications. The scientists hope to ratchet up the efficiency of their device up to as much as 30 percent in forthcoming research.

In the future, producing devices based on the nano procedure could prove extremely cost-efficient because it may be possible to use standard ink-jet printing technology to construct plastic-based optical devices.

Before the discovery, there were only a limited number of materials that could be used for optical communications. John Prohaska, director of technology and research at the Center for Advanced Fiberoptic Applications, a Massachusetts-based industry consortium, said the discovery is an “important development” for optical communications. “It could conceivably give a price advantage or a performance advantage,” he said.

Moti Margalit, chief technology officer of Lambda Crossing, an Israeli optical component startup, also confirmed that the development is a breakthrough for the optics industry but said the benefits of future applications may not necessarily be price-related.

“When we look forward we are seeking a platform that allows us to integrate both optics and plastics in a cheap and reliable way,” he said. “Since these materials can be easily applied over a variety of substances and substrates they open up new possibilities for integration.”


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