Researchers at Purdue University have created tiny holograms using a "metasurface" capable of the ultra-efficient control of light, representing a potential new technology for advanced sensors, high-resolution displays and information processing.
The metasurface, thousands of V-shaped nanoantennas formed into an ultrathin gold foil, could make possible "planar photonics" devices and optical switches small enough to be integrated into computer chips for information processing, sensing and telecommunications, said Alexander Kildishev, associate research professor of electrical and computer engineering at Purdue University.
Laser light shines through the nanoantennas, creating the hologram 10 microns above the metasurface. To demonstrate the technology, researchers created a hologram of the word PURDUE smaller than 100 microns wide, or roughly the width of a human hair.
"If we can shape characters, we can shape different types of light beams for sensing or recording, or, for example, pixels for 3-D displays. Another potential application is the transmission and processing of data inside chips for information technology," Kildishev said. "The smallest features - the strokes of the letters - displayed in our experiment are only 1 micron wide. This is a quite remarkable spatial resolution."
Metasurfaces could make it possible to use single photons - the particles that make up light - for switching and routing in future computers. While using photons would dramatically speed up computers and telecommunications, conventional photonic devices cannot be miniaturized because the wavelength of light is too large to fit in tiny components needed for integrated circuits.
Nanostructured metamaterials, however, are making it possible to reduce the wavelength of light, allowing the creation of new types of nanophotonic devices, said Vladimir M. Shalaev, scientific director of nanophotonics at Purdue's Birck Nanotechnology Center and a distinguished professor of electrical and computer engineering.
Via Dr. Stefan Gruenwald