In recent years, researchers have used metamaterials to bend light in ways not found in nature and even make objects disappear from view. Now, a team from Purdue University (Indiana, U.S.A.) has used a tiny-patterned “metasurface” to create ultra-thin red-light holograms (Nature Commun. 4, 2807).
The metasurface designed by researchers at Purdue's Birck Nanotechnology Center consists of nanosized perforations into a 30-nm-thick gold layer on a glass substrate. The subwavelength-scale voids, shaped with a focused ion beam, act as tiny plasmonic antennas to control the phase of the 676-nm laser light beamed through the metasurface.
CAMBRIDGE, England, July 30, 2014 — A new laser-pulse technique has been used to create light-altering metamaterials in larger quantities than other techniques. Researchers at the University of Cambridge have developed a new method of nanoassembly involving plasmon-induced laser threading of gold nanoparticle strings to produce conducting threads 12±2 nm wide. For more information, visit www.cam.ac.uk.
An efficient route to manufacturing nanomaterials with light through plasmon-induced laser-threading of gold nanoparticle strings. Courtesy of Ventsislav Valev/University of Cambridge.
PHILADELPHIA, AUSTIN, Texas, and BENEVENTO, Italy, Jan. 13, 2014 — The discovery that metamaterials can be designed to perform "photonic calculus" as lightwaves pass through them could give rebirth to analog computers.
The theoretical metamaterial could perform a specific mathematical operation on a lightwave’s profile, such as finding its first or second derivative, as that lightwave passes through it, says a team from the University of Pennsylvania, University of Texas at Austin and University of Sannio. For more information, click here.
Computational metamaterials could almost instantly perform operations on the original wave, such as the light coming in through the lens of a camera, without conversion to electronic signals. Essentially, mechanical gears and electrical circuits used in original analog computers are replaced with optical materials that operate on lightwaves.
This theoretical metamaterial, working like an analog computer, produces the derivative of the incoming lightwave's profile.