Entanglement from Triangular Dots

Entanglement is an essential resource for the implementation of quantum information processing. An efficient source of high-purity entangled photons is of particular importance since it would play a key role in realizing practical quantum communications. A team headed by Dr. Takashi Kuroda, who is a Principal Researcher in the NIMS Photonic Materials Unit, and Dr. Takaaki Mano, a Senior Researcher in the same unit, in joint research with Hokkaido University and the University of Toulouse (France), succeeded in generating highly-entangled photons using a naturally symmetric quantum dot cascade. Their photon source consists of strain-free GaAs dots self-assembled on a triangular symmetric (111)A surface. The measured photons strongly violate Bell’s inequality without postselection, which is an important step towards scalable quantum communication applications. This research achievement will enable long-distance transmission of quantum information, which had not been possible in the past. This result was published online on July 19 in the American scientific journal Physical Review B, where it was selected as an Editor's Suggestion.
http://dx.doi.org/10.1103/PhysRevB.88.041306