Tiny tubes tune in colors

For more than a century, electric devices have been transmitting and receiving radio signals via antennas that range from skyscraping radio towers to telescoping cell phone aerials. Now, scientists have shown that far smaller antennas can snatch visible light waves from the air.

COLOR CODED. A carpet of vertically oriented carbon nanotubes shimmers with rainbow reflections because different-length tubes within the carpet respond to different colors.