On-chip microlaser driven sources of indistinguishable photons for quantum networks

This project aims at developing highly integrated quantum light sources based on so-called quantum dots, which are tiny semiconductor structures that function like artificial atoms. Our device concept goes well beyond existing approaches by using monolithically integrated microlasers to trigger the emission of single photons from these quantum dots. Being electrically driven, the microlasers combine user-friendly operation with ultra-small footprint. Our advanced on-chip resonant excitation scheme ensures excellent quantum nature of emission i.e. only one photon at a time and never two or more while subsequent photons will be indistinguishable in all their properties. To meet the challenging technological requirements of our concept we apply state-of-the-art nanoprocessing and deterministic device technology. This way we realize low threshold whispering-gallery microlasers which emit into waveguide systems with deterministically integrated quantum dots. The waveguide systems include splitting elements, resonators to maximize the photon extraction efficiency, as well as non-linear elements for on-chip frequency conversion of single photons. Overall, our project creates the foundations for complex and highly functional quantum circuitry to act as important building blocks for future quantum communication and quantum computation systems.