New single-photon source could boost quantum cryptography

A simple source of single photons that is powered only by an electric current has been developed by an international team of researchers. The device, a modification of the traditional semiconductor p–n junction called a p–i–n junction, is made from diamond and is one of the first single-photon emitters to work at room temperature that does not need to be pumped with a laser – another research group working independently has demonstrated a similar device. In the short term, the device could help to make "unbreakable" quantum cryptography a more viable endeavour. In the longer term, the researchers hope the devices might open up new avenues for research in quantum computing and other research in quantum-information theory.