Scientists have created a new microelectronic device that can emit the smallest amount of light possible, a breakthrough that may lead to absolute confidentiality in communications involving finance, health care and other fields.A perfectly secure message impossible to eavesdrop on depends on communication signals that contain only one packet of light, or photon. Ordinary light sources, however, are not able to reliably generate these incredibly dim, one photon pulses.

Researchers working with the University of Cambridge in England have invented the first single photon source driven solely by electric current – a new type of light-emitting diode 10 times thinner than a human hair, based on electron clusters known as quantum dots.