Diamond Defects Enhance Single-Photon Emission

Nanodiamonds containing atomic-scale defects can enhance metamaterials’ emission of single photons — an important attribute of future quantum computers.

A team at Purdue University, in cooperation with Russian researchers, coupled nanodiamonds with nitrogen vacancy centers with a metamaterial lattice made of titanium nitride (TiN) and aluminum scandium nitride (Al_xSc_1-xN). The metamaterial is pumped by a laser.

“These results indicate that the brightness of the nanodiamond-based single-photon emitter could be substantially enhanced by placing such an emitter on the surface of the hyperbolic metamaterial,” said Purdue professor Dr. Alexander Kildishev. “The single-photon emitters could be used to build highly efficient, room-temperature, CMOS-compatible single-photon sources.”

Nanodiamonds have been added to the surface of a hyperbolic metamaterial to enhance the production of single photons, a step toward quantum computers and communications technologies. Courtesy of the Birck Nanotechnology Center at Purdue University.

A nitrogen vacancy center is an atomic-scale defect formed in the diamond lattice by substituting a nitrogen atom for a carbon atom.

Placing a nanodiamond containing an NV center on the surface of hyperbolic metamaterials not only enhances the emission of photons, but also changes the pattern of light emitted, a trait that could be important for the development of quantum devices.

Nitrogen vacancies may also play a role in data storage because information may be encoded in nuclear or electron spin state of the center.

Future research may include work to improve the system with devices that combine the hyperbolic metamaterial with nanoantennas and optical waveguides to increase its efficiency and make it more compact.

“We are interested in causing it to emit faster so that we can increase the rate of these photons coming out,” Kildishev said.

The research was published in Laser & Photonics Reviews (doi: 10.1002/lpor.201400185).

For more information, visit www.purdue.edu.