Periodic Reporting for period 1 - SinglePass (A cold-atom photonic-crystal-waveguide interface for efficient quantum operations in single pass) Okres sprawozdawczy: 2021-03-01 do 2023-02-28 Podsumowanie kontekstu i ogólnych celów projektu Processing quantum information at the nodes of a quantum network requires the implementation of a deterministic coupling with another qubit, in the form of a material quantum system, through nonlinear quantum optics. A novel approach for achieving the strong photon-qubit coupling required for nonlinear quantum optical protocols relies on the emerging field of integrated photonic nanostructures, waveguides in particular, coupled to emitters. This new paradigm relies on two ingredients to enhance the atom-photon coupling. In a nanophotonic waveguide, the optical mode is readily confined, providing a transversal increase in energy density. Longitudinal structuration can further enhance the coupling by manipulating the dispersion relation to exploit slow modes near the optical band gap. Coupling atoms to such integrated photonic nanostructures would enable to scale up to ensembles of quantum emitters by harnessing their inherent indistinguishability. SinglePass aimed at coupling atoms to Photonic Crystal Waveguides (PCW) exhibiting slow modes for enhancing the atom-light coupling. Reaching the strong coupling regime with such a waveguide quantum electrodynamics (wQED) platform with atoms offers the prospect of realizing for instance an all-guided single-photon transistor in single pass. The fellow obtained a permanent academic position during the course of the fellowship, which led to the early termination of the action. Prace wykonane od początku projektu do końca okresu sprawozdawczego oraz najważniejsze dotychczasowe rezultaty A first objective of the project was to integrate PCWs with cold atoms in a new experimental setup. A new setup for cooling and trapping rubidium atoms was developed and has been built and PCWs are being fabricated by the host’s partners. The next step will be to combine the two and to transport cold atoms in the vicinity of the PCWs.A critical requirement for reaching the strong coupling regime in this wQED platform is to trap the atoms in the evanescent field of guided modes. A significant step was attained to this end by the development of a Python package for computing such dipole traps: nanotrappy. This package was used to design the PCWs that will be used, and has been made available in open source to the community. Innowacyjność oraz oczekiwany potencjalny wpływ (w tym dotychczasowe znaczenie społeczno-gospodarcze i szersze implikacje społeczne projektu) The fellowship allowed for the fellow to gain improved knowledge and exposure to the field of nanophotonics, as well as valuable experience in training students. The early progress sets a strong platform for the continued work in wQED by the researcher. w1-lowres.png
