1High Frequency Acousto-electric Single Photon Source

We propose a single optical photon source for quantum cryptography based on the acousto-electric effect. Surface acoustic waves (SAWs) propagating through a quasi-one-dimensional channel have been shown to produce packets of electrons which reside in the SAW minima and travel at the velocity of sound. In our scheme these electron packets are injected into a p-type region, resulting in photon emission. Since the number of electrons in each packet can be controlled down to a single electron, a stream of single (or N) photon states, with a creation time strongly correlated with the driving acoustic field, should be generated. 2Single photon states at optical frequencies provide an ideal resource for quantum communication and information processing1. The recent demonstration of teleportation2 using entangled photon pairs generated by parametric down-conversion is an example. In addition, there are proposals and experimental schemes to use single photons for quantum computation3,4, but the most important and experimentally relevant application of single photon sources is in secure optical communications using quantum cryptographic protocols5. No true, unconditional, single photon sources exist at optical frequencies so other sources ar