Quantum dots generate identical photons

1 min read

Looking to bring the age of quantum computing a step nearer to reality, researchers from the Cavendish Laboratory at Cambridge University have developed a technique which enables single photons with tailored properties to be generated from solid state devices. According to the researchers, the photons are identical in quality to lasers.

Single photons, says the team, will form an integral part of distributed quantum networks. It says photons are the natural choice for quantum communication as they not only carry information quickly and reliably across long distances, they can also take part in quantum logic operations. However, the quality of photons generated from solid state qubits, including quantum dots, can be affected by decoherence within the materials and each can be different. The research team used a semiconductor Schottky diode device containing individually addressable quantum dots as their photon source. The team found that, when the source was operated under weak excitation, photon decoherence could be avoided and the photons generated were identical to lasers in terms of coherence and waveform. Dr Mete Atature from the Department of Physics, who led the research, said: "We are now achieving a high rate of single photons which are identical in quality to lasers with the further advantage of coherently programmable waveform – a significant paradigm shift to the conventional single photon generation via spontaneous decay."