Coaxial Cables Twinkle in Scientist’s Eye

R&D DIGEST

Nanoscopic metal cables could be harnessed to create artificial retinas, says Jakub Rybczynski from Boston College. The coaxial cable is shrunk by a factor of 10,000 so that the diameter is smaller than the wavelength of visible light.

Rybczynski says the cable is similar to any coaxial cable used in medical applications. It is a central wire that is surrounded by a layer of dielectric material and then wrapped in a metal sheath. Radio waves move along the central wire. The big difference is that cable is nanoscopic, measuring only 300 nm in diameter, and it transports light waves rather than radio waves. It is shorter than the shortest wavelength of visible light and is invisible to the human eye.

The core of Rybczynski's cable is a carbon nanotube.

The nanocables are not candidates to replace optical fibers. So far, the longest ones stretch only 20 µm, and longer cables will only carry light a maximum of about 50 µm—roughly 100 wavelengths.

However, being able to transmit light on the nanoscale scale could have significant applications, from building quantum computers to creating artificial retinas. To serve as artificial retinas, the team would need to assemble arrays with optical antennas on one end and an electrical output at the other.

The paper appeared in the January 8 edition of Applied Physics Letters.

Copyright ©2007 Medical Device & Diagnostic Industry