U.S. Researchers Invent Antenna for Light

[David Farber <dave () farber net>]

Begin forwarded message:

From: Jean Armour Polly <mom () netmom com>
Date: September 19, 2004 8:26:26 AM EDT
To: David Farber <dave () farber net>
Subject: U.S. Researchers Invent Antenna for Light

U.S. Researchers Invent Antenna for Light
Fri Sep 17, 1:59 PM ET

WASHINGTON (Reuters) -  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. 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, pictured on the Internet at  
http://www.aip.org/png/2004/221.htm, 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.
http://story.news.yahoo.com/news?tmpl=story&cid=570&e=13&u=/nm/ 
science_antenna_dc

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