Trapped atoms and collective emission on an integrated nanophotonic microring circuit

Integrating atoms with nanophotonic circuits enables strong atom-light interactions and provides a potentially scalable platform for the study of many-body physics and quantum optics. In this poster, we demonstrate the ability to trap atoms on top of a nanophotonic chip and, by performing degenerate Raman sideband cooling, we can efficiently evanescently couple atoms to a microring resonator. We study how the densely packed atomic ensemble collectively couples to both the resonator mode and other free-space or non-guided modes. Specifically, we show superradiant emission in the resonator mode and reveal signatures of subradiant or superradiant emission into other free-space modes when the system is initially driven into a steady-state or a timed-Dicke state, respectively. To investigate the fast coherence build-up in the atomic ensemble, we also prepare the atoms in a fully inverted state using nanosecond pulses and study the subsequent decay dynamics. Our demonstration of collective effects on an integrated nanophotonic chip paves the way towards applications in quantum metrology, sensing, and nonlinear optics.