MOSCOW, August 3. /TASS/ Scientists from the Moscow Institute of Physics and Technology (MIPT), the University of Siegen, and the European Laboratory for Non-Linear Spectroscopy have elucidated that a synthetic diamond with artificially created defects can act as a quantum emitter which might be applied for creating ultrapower quantum computers and in quantum encrypting systems, as reported by the press-service of MIPT.

The study published recently in the New Journal of Physics is devoted to the development of efficient electrically-driven single-photon sources – devices that emit single photons when an electrical current is applied. Using such devices, one can generate single photons one after another, but not simultaneously, like in electric bulb.

For quantum computing, it is crucial to have the ability to manipulate individual photons, as the working principle of quantum computers rests on the using single photons as an information unit. With the single-photon devices, it is possible not only to increase the energy efficiency of the existing data processing and data transmission devices by more than one thousand times but also to build quantum computers and to improve the existing cryptography systems.

Until recently, the quantum dots (nanoscaled semiconductor particles) have been thought to be the most promising candidates for the single-photon sources. However, they operate only at very low temperatures, with the cooling process being quite expensive because of liquid nitrogen or even liquid helium needed for that.

The researchers have found out that the defect in the crystal lattice of diamonds, for instance, the inclusion of foreign atoms like silicon or nitrogen, emit single photons when the electric current passes through the diamond. The calculations show that doped diamond emitters create a very bright photon beam consisting of more than 100,000 photons per second. It is enough to increase the data transmission rate by the orders of magnitude if compared to the currently applied photon sources. Importantly, the diamond emitters function at room temperature.

Diamond photon emitters can replace attenuated lasers used in the existing system of quantum cryptography. The diamond-based sources allow for sending exactly the required amount of photons, whereas the attenuated lasers are known for the misfire, emitting zero or multiple photons in a random way which in turn increase the danger of signal intercept by a violator.