Nanoantennas could lead to optical innovations

ScienceDaily : Researchers at Purdue University have designed V-shaped gold and silicon nanoantennas that can cause broadband light to bend in unusual ways, including with negative angles of refraction. Extending earlier work by a group at Harvard University, the Purdue team showed that an array of the nanoantennas at a material interface can change the phase and propagation direction of light over a broad range in the near-IR. The arrays, much thinner than the light’s wavelengths, produced dramatic deviations from the conventional laws governing how light refracts as it passes from one material to the next. Says team member Vladimir Shalaev, “Not only the bending effect, refraction, but also the reflection of light can be dramatically modified by the antenna arrays on the interface, as the experiments showed.” Shalaev is the scientific director of nanophotonics at Purdue’s Birck Nanotechnology Center and one of the authors of a paper published online yesterday in Science. The team’s technique could have a range of technological applications, including in fiber-optic telecommunications and in more powerful microscope lenses.