Nature Photon. doi:10.1038/nphoton.2009.003(2009)

Unlike X-rays, terahertz or 'submillimetre' radiation can penetrate organic samples without damaging them, and so holds promise for medical diagnostics. But there is a stumbling block on the path to such technologies: terahertz waves have proved difficult to manipulate.

Hou-Tong Chen at the Los Alamos National Laboratory in New Mexico and his colleagues have now developed a device that controls the phase of terahertz waves. This makes it possible for researchers to store and transmit information with terahertz radiation by varying the voltage across a 'metamaterial' — one made from tiny components that are similar in size to the wavelength of the terahertz waves.

The metamaterial modulator works as well as analogous devices for manipulating optical waves, but at much higher speeds.