Warburton, Richard

Date:   Thursday, June 11, 2020
Time:   10:00
Place:   scheduled Zoom meeting
Host:    Klaus Ensslin

Single photon emitters in a cavity

Richard J. Warburton
University of Basel

Single photon emitters exist in semiconductors (quantum dots) and in diamond (colour centres). One way to funnel the photons into one specific mode is to embed the emitter in a resonant cavity. Recently, we succeeded in our longstanding quest to embed gated quantum-dots into a small, high quality-factor cavity. The light-matter interaction becomes profoundly quantum in character: adding just one photon to the cavity shifts the resonances; we observe a coherent exchange between a single photon in the cavity and a single excitation in the “atom”. In the case of a colour centre in diamond, here the nitrogen-vacancy centre, the cavity boosts the probability of creating a coherent photon, from just 3% in bulk diamond to close to 50%, while preserving the excellent spin coherence. These results open up perspectives in quantum technology: fast and efficient sources of single photons and entangled spin-photon pairs are within reach; photonic cluster states hover on the horizon.