Quantum dot based quantum optics

We explore the possibility to implement a solid state quantum network based on semiconductor quantum dots in microcavities. The cavity enhanced light matter coupling allows creating a very efficient interface between the quantum dot and the optical far field. We deterministically position a single quantum dot in a connected pillar microcavity combined with a p-i-n junction and fabricate tunable ultrabright single photon sources. The collection efficiency is shown to exceed 60% and the indistinguishability of photons successively emitted by one device is in the 80-97% range depending on the excitation conditions. The quantum interference of photons emitted by two remote devices is shown to be greatly enhanced by the acceleration of spontaneous emission. Finally, we explore the possibility to store the quantum information on a longer time scale using the spin states of a hole in a quantum dot. We demonstrate the nondestructive measurement of a single spin by monitoring the spin dependent rotation of polarization of a probe beam: a polarization rotation of ±6° is observed depending on the spin state.