High-Quality Synthetic Diamond Used In Experimental Quantum Computing Research
SANTA CLARA, Calif. (Feb. 18, 2015)—Element Six—the world leader in synthetic diamond supermaterials and member of The De Beers Group of Companies—announced that in collaboration with MIT and Brookhaven National Laboratory, it has demonstrated a significant step toward a synthetic diamond quantum information processor. Utilizing nano-engineered synthetic diamond the team fabricated optical structures around specific atom-like defects in the diamond lattice while maintaining exceptional quantum properties. The impurities, called Nitrogen-Vacancy centers, have shown significant promise in recent years as quantum bits, or “qubits,” that can serve as memories and logic elements in quantum communication or even quantum computing. Unlike most other host materials, the diamond crystal lattice forms a low ‘noise’ environment for such color centers. As a result, electrons and nuclei in the color centers are well isolated from their environment and can have exceedingly long-lived quantum coherence compared to other materials even at room temperature.
“Manipulation and control of quantum information is an extremely exciting field to be part of. The exploration and new techniques led by the team of MIT researchers, leveraging the unique properties of Element Six’s synthetic diamond, have shown great promise toward diamond quantum technology,” remarked Adrian Wilson, head of the Technologies Group at Element Six.
The Element Six team worked closely with Professor Dirk Englund to define diamond material required which was fabricated using chemical vapor deposition techniques. By careful control of the synthesis process, the Element Six team produced synthetic diamond with a very low level of impurities and a concentration of Nitrogen-Vacancy color centers such that individual color centers can be observed with an optical microscope under laser illumination. Using this material the MIT researchers developed a new patterning technique to place a structure around a color center by affixing a silicon membrane, containing a ladder pattern, on to the diamond and then employing plasma etching to fabricate structures in the diamond. Measurements of the properties of color centers in this structured diamond show that the delicate quantum properties have been unaffected by the fabrication process. With this new structure and fabrication technique, the resulting structures exhibits a coherence time around 200 microseconds, about a hundred times longer than previously reported memory times in such quantum interfaces. This is a significant increase in the coherence time in a structured diamond which forms an important step toward building large-scale quantum systems consisting of many interconnected quantum memories.
Englund commented, “Synthetic diamond is an ideal host material for such atom-like qubits. Element Six has led the way in producing high-purity synthetic diamond that has made this advance possible for our team.”
Quantum computers in principle can solve problems that cannot be solved using current computing technology. However, for practical quantum computers, there is still work to be done to link many qubits together, but this result is a significant step toward that goal. There are also some nearer-term applications that this advancement can be applied, including quantum-secured communication links in which these type of diamond structures act as network repeaters.
