Nanoscale Mirrors Make Data Transfers More Secure
February 05, 2015By constructing tiny "mirrors" to trap light around impurity atoms in diamond crystals, researchers at the Massachusetts Institute of Technology (MIT) and the U.S. Department of Energy's (DOE) Brookhaven National Laboratory increased the efficiency with which photons transmit information. Such spin-photon interfaces could open the door to quantum computers and long-distance cryptographic systems.
The memory elements described in this research are the spin states of electrons in nitrogen-vacancy (NV) centers in diamond. The NV consists of a nitrogen atom in the place of a carbon atom, adjacent to a crystal vacancy inside the carbon lattice of diamond.
“To increase the interaction between photons and the NV, the researchers built an optical cavity-a trap for photons-around the NV”, says MIT's Dirk Englund, who led the research, now published in Nature Communications.
These cavities consist of layers of diamond and air tightly spaced around the impurity atom of an NV center. At each interface between the layers there's a bit of reflection. Photons that enter bounce back and forth up to 10,000 times, enhancing their chance of interacting with the electrons in the NV center.
This research may enable the long-distance transfer of quantum-encoded information over fiber optic cables. Such information could be made completely secure, Englund reports, because any attempt to intercept or measure the transferred information would alter the photons' properties, thus alerting the sender and the recipient to the possible presence of an eavesdropper.
Question or comment on this article? Contact an editor: engineering360editors@ihs.com