INTERCEPTING the keys to coded messages could get a lot harder, now that
Ataç Imamoglu and his team at the University of California, Santa
Barbara, have developed a “quantum dot” that can emit light one photon at a
time. This will allow keys to be represented by a sequence of pulses of
individual photons. A single photon cannot be split, so any snoopers trying to
listen in to the sequence will have to interact with the light particles and
give themselves away.
When the dot is excited by laser light, it gives up its energy by emitting
just one photon…
