Telecom wavelength semiconductor quantum dot single photon sources for quantum photonics
Prof. Dr. Sven Höfling (Julius-Maximilians-Universität Würzburg)

As high-performant sources of single photons, epitaxial quantum dots can be considered as a semiconductor launchpad for quantum photonic technologies. There is still a variety of challenges to tackle on the road to an ideal source of single or entangled photons for quantum photonic applications. Here, we present an overview of recent developments in our group on the engineering of single-photon sources for quantum photonic applications made from III-V semiconductor quantum dots grown by molecular beam epitaxy. By integrating InAs/InP quantum dots into circular Bragg grating resonators, Purcell-enhanced single-photon emission with a Purcell factor of ≈7 in the telecom C-band was achieved. Low multi-photon emission probabilities are obtained, and Hong-Ou-Mandel two-photon interference is demonstrated. By further improving the epitaxial growth, photonic design and excitation schemes, we were able to obtain record two photon interference visibilities. We furthermore report on recent progress made in our group towards deterministic generation of one-dimensional photonic cluster states directly in the telecom C-Band as a resource for quantum repeaters and quantum computers.