A tunable polarizer / optical antenna

3t3 3t3 at comcast.net
Fri Nov 23 18:13:44 CST 2012

New research at Rice University -

Nanorods can function as efficient optical antennas for use in improving 
optical switches for faster data communications.

Liquid crystals in this homogenous phase block light from nanorods 
turned one way, while letting light from nanorods pointed another way 
pass through a polarizer to the detector.

The team at Rice University expects to be able to control light from any 
nanostructure that scatters, absorbs, or emits light, even quantum dots 
or carbon nanotubes. “The light only has to be polarized for this to 
work,” said Link, who studies the plasmonic properties of nanoparticles.

The researchers said that what happened then was remarkable. When the 
team applied as little as four volts to the electrodes, liquid crystals 
floating in the vicinity of the nanorods aligned themselves with the 
electric field between the electrodes while crystals above the 
electrodes, still under the influence of the cover-slip coating, stayed put.

The new configuration of the crystals — called a twisted nematic phase — 
acted like a shutter that switched the nanorods’ signals like a traffic 

“We don't think this effect depends on the gold nanorods,” Link said. 
“We could have other nano objects that react with light in a polarized 
way, and then we could modulate their intensity. It becomes a tunable 


     Terry McCarty
    3t3 at comcast.net

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