Quantum Rainbow Photon Gun Unveiled

A photon gun capable of reliably producing single photons of different colours could become an important building block of a quantum internet
04/23/2012

We've heard much about the possibility of a quantum internet which uses single photons to encode and send information protected by the emerging technology of quantum cryptography.

The main advantage is of such a system is perfect security, the kind of thing that governments, the military, banks and assorted other groups would pay handsomely to achieve.

One of the enabling technologies for a quantum internet is a reliable photon gun that can fire single photons on demand. That's not easy.

One of the significant weaknesses of current quantum cryptographic systems is the finite possibility that today's lasers emit photons in bunches rather than one at a time. When this happens, an eavesdropper can use these extra photons to extract information about the data being transmitted.

So there's no shortage of interest in developing photon guns that emit single photons and indeed various groups have made significant progress towards this. the rest