Tunable graphene microribbons made to respond to terahertz light

posted Sep 10, 2011, 11:35 AM by Hatef Sadeghi
Researchers from Berkeley a microscale device that responds to light at terahertz frequencies. The device is an array made of graphene microribbons. By varying the width of the ribbons and the concentration of charge carriers in them, the scienstists were able to control the collective oscillations of electrons (plasmons) in the microribbons.
The graphene microribbon array can be tuned in three ways. Varying the width of the ribbons changes plasmon resonant frequency and absorbs corresponding frequencies of terahertz light. Plasmon response is much stronger when there is a dense concentration of charge carriers (electrons or holes), controlled by varying the top gate voltage. Finally, light polarized perpendicularly to the ribbons is strongly absorbed at the plasmon resonant frequency, while parallel polarization shows no such response.

More info: http://www.physorg.com/news/2011-09-tunable-graphene-device-tool-kit.html