S. Reitzenstein

P. Schnauber, J. Schall, S. Bounouar, T. Höhne, A. Singh, K. Sirinvasan, M. Davanco, J.-D. Song, S. Burger, S. Rodt, S. Reitzenstein
The deterministic integration of quantum emitters into on-chip photonic elements is crucial for the implementation of scalable on-chip quantum circuits. Recent activities in this field include hybrid QD-waveguides for enhanced photon in-coupling and the controlled integration of QDs using multistep-lithography as well as AFM tip transfer. Here, we report on the deterministic integration of single quantum dots (QD) into on-chip beam splitters using in-situ electron beam lithography (EBL). In this advanced single-step technique, photonic building blocks are patterned on top of chosen QDs immediately after spatial and spectral pre-characterization via cathodoluminescence mapping at 10 K. To realize 50/50 coupling elements, we chose tapered multimode interference (MMI) splitters which feature relaxed fabrication tolerances and robust 50/50 splitting ratio. We demonstrate the functionality of the deterministic QD-waveguide structures by µPL spectroscopy and by studying the photon cross-correlation between the two MMI output ports. The latter confirms single-photon emission and on-chip splitting associated with g(2)(0) ≪ 0.5. Moreover, the deterministic integration of QDs enables the demonstration and controlled study of chiral light-matter effects and directional emission in QD-WGs, as well as the realization of low loss heterogenous QD-WG systems with excellent quantum optical properties in terms of high photon purity and high photon indistinguishability.