----- Original Message ----- From: "Robert G. Seeberger" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, September 18, 2004 10:23 AM Subject: Researchers invent antenna for light
> http://www.cnn.com/2004/TECH/science/09/17/light.antenna.reut/index.html > > Researchers said on Friday they have invented an antenna that captures > visible light in much the same way that radio antennas capture radio > waves. > They say the device, using tiny carbon nanotubes, might serve as the > basis for an optical television or for converting solar energy into > electricity once properly developed. > > Radio and television signals are captured using antennas close to the > size of the wavelength of broadcast radiation. These are often huge -- > thus the need for tall antennas. > > In a receiver, the wave excites electrons into meaningful currents, > which are amplified and tuned to carry sound and pictures. > > But light is carried by photons -- >tiny packages that have the > properties of waves and particles. So are radio waves. :-) Radio waves have longer wavelengths, lower freqencies, and less energy per photon than do light waves. >They are visible because cells in > the eye capture them, but no one had been able to make a device small > enough to act as an antenna. > Yang Wang and colleagues at Boston College used carbon nanotubes, > which are microscopic structures built out of carbon atoms. > > The tubes are aligned randomly. > > The light excites miniature electrical currents, they write in the > latest issue of the journal Applied Physics Letters. > > A visible-light antenna might work by receiving a television signal > superimposed onto a laser beam sent down an optical fiber, the > researchers said. > > This technology may improve the efficiency and quality of television > signals. > > Or it could be used as the basis of an efficient solar energy device > that turns incoming light into an electrical charge to be stored in a > capacitor, they said. Sigh, violating conservation of both energy and charge. I think I know what actually was done, but this was _very_ poorly written. Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
