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Carbon Nanotube Antenna for Light
Suidae writes "Researchers at Boston College are reporting that carbon nanotubes can be used to build an antenna that receives optical wavelengths in much the same way a radio antenna receives longer wavelengths. The electrical effects can not yet be directly measured as diodes that operate at optical frequencies would be required, but secondary radiation from the excitation can be observed. Potential applications include fiber optic data transmission and photovoltaics."
It's interesting that this should come up, as last spring or so, I was sitting on the presentation of a paper about doing this with far-infrared. Conventional lithographic techniques were used to make waveguides and rectifiers. Photons entering the wave guide caused currents when they struck the walls, which were picked up and rectified by interesting devices that worked by exploiting ballistic electron transport (looked like a wedge inside a T-joint; electrons flowing in one direction were preferentially scattered).
Frequency limit of this technique was related to the sizes of their structures, but I didn't get the impression that it would work at optical wavelengths. Still very nifty, though.
[The paper was presented at CCECE 2004, but I'm having difficulty finding a citation.]
Patents by Alvin Marks
The carbon nanotube guys didn't produce DC electricity because they don't have a super-fast rectifier. Alvin Marks has patented a design for one. Dunno if it's actually been tested, though.
Hmmm, it looks like the femto-diode patent has expired (search for 4,720,642).