Nano- and microscale optical systems have shown great progress towards realizing efficient and
scalable quantum interfaces through enhanced atom-field coupling in both resonators and
waveguides. Beyond these conventional topologies, new opportunities emerge from the
integration of cold atoms with nanoscale photonic crystal devices, which exploit the flexibility for
modal and dispersion engineering. In photonic crystal waveguides (PCW), engineered lightmatter
interactions enable to explore novel quantum transport, quantum many-body phenomena,
and Casimir-Polder forces.
We have developed an integrated optical circuit with a PCW capable of both trapping and
interfacing atoms with guided photons. From superradiance of trapped atoms, we infer the
average atom number of 2.6 (0.3) and the fraction of single-atom radiative decay into the PCW to
be Γ1D/Γ’ = 1.0 (0.1), where Γ1D (Γ’) is the atomic spontaneous emission rate into the guided (all
other) mode (s). We discuss progress towards dissipation engineering, which should enable a
regime where coherent long-range interactions are dominant in the system.