Quantum transduction of telecommunicationsband single photons from a quantum dot by frequency upconversion (Englisch)

Transducing non-classical states of light from one wavelength to another is required for integrating disparate quantum systems that take advantage of telecommunications-band photons for optical-fibre transmission of quantum information and near-visible, stationary systems for manipulation and storage. In addition, transducing a single-photon source at 1.3 micron to visible wavelengths would be integral to linear optical quantum computation because of near-infrared detection challenges. Recently, transduction at single-photon power levels has been accomplished through frequency upconversion, but it has yet to be demonstrated for a true single-photon source. Here, the authors transduce triggered single photons from a semiconductor quantum dot at 1.3 micron to 710 nm with 21 percent (75 percent) total detection (internal conversion) efficiency. The authors demonstrate that the upconverted signal maintains the quantum character of the original light, yielding a second-order intensity correlation, g(t), that shows that the optical field is composed of single photons with g(0) = 0.165 < 0.5.