Search Menu
Photonics Media Photonics Buyers' Guide Photonics Spectra BioPhotonics EuroPhotonics Vision Spectra Photonics Showcase Photonics ProdSpec Photonics Handbook

Metamaterial a One-Way Street for Visible Light

Facebook Twitter LinkedIn Email Comments
A structure based on hyperbolic metamaterials allows visible light to pass in only one direction, creating new possibilities for optical circuits and biosensing.

Developed at the National Institute of Standards and Technology, the device integrates a silver and silicon dioxide glass nanostructure with sub-wavelength diffractive gratings made of chromium.

The 20-layer nanostructure, created using thin-film deposition techniques, is opaque to external light but allows light to propagate inside over a narrow range of angles. A grating on one face of the nanostructure bends incident light, allowing it to enter. Another grating on the opposite face permits the light to exit, but at a different angle than it entered.

Schematic of NIST's one-way metamaterial. Forward travelling green light (left) or red light passes through the multilayered block and comes out at an angle due to diffraction off of grates on the surface of the material. Light travelling in the opposite direction (right) is almost completely filtered by the metamaterial and can't pass through. Courtesy of Ting Xu/NIST.

The gap spacing of the second grating is slightly different from the first, and so it bends incident light either too much or not enough to enter the silver-glass nanostructure. The researchers said about 30 times more light passed through in the forward direction than in reverse.

Devices were tested at 532 nm (green) and 633 nm (red) wavelengths and displayed broadband, efficient asymmetric optical transmission with contrast ratios > 14 dB, the researchers said.

Similar devices have been made to manipulate IR light and microwaves, but the NIST project is the first applied to the visible spectrum, the researchers said. Without the silver-glass nanostructure, they said, the grates would have to be fabricated and aligned more precisely than is possible with current techniques.

“This three-step process actually relaxes the fabrication constraints,” said NIST researcher Henri Lezec.

In the future, the researchers said, the new structure could be integrated into photonic chips and nanoparticle detectors for biosensing applications. Like the chromium grates, nanoscale particles also can deflect light at angles steep enough to travel through the hyperbolic metamaterial and come out the other side.

"I think it's a cool device where you would be able to sense the presence of a very small particle on the surface through a dramatic change in light transmission," Lezec said.

The research was published in Nature Communications (doi: 10.1038/ncomms5141).

For more information, visit

Photonics Spectra
Oct 2014
An electromagnetic wave lying within the region of the frequency spectrum that is between about 1000 MHz (1 GHz) and 100,000 MHz (100 GHz). This is equivalent to the wavelength spectrum that is between one millimeter and one meter, and is also referred to as the infrared and short wave spectrum.
AmericasBiophotonicsbiosensingchromiumCommunicationsdepositionFiltersGaithersburgHenri LezecIRMarylandmaterialsmetamaterialsmicrowavenanoNational Institute of Standards and TechnologyNature CommunicationsNISToptical circuitsopticsphotonic chipsphotonic integrated circuitsResearch & TechnologysilverTech Pulsethin-filmsvisible lighthyperbolicsilicon dioxide glassdiffractive gratingsasymmetric optical transmission

back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2020 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA, [email protected]

Photonics Media, Laurin Publishing
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.