Coupling single atoms and molecules to nanophotonic resonators

Abstract

The integration of cold neutral atoms with nanophotonic circuits offers significant potential as a light–matter interface for a wide range of applications ranging from fundamental studies in quantum optics, quantum many– body physics, quantum networks to even ultracold chemistry. Here, we describe the design and realization of a novel platform where an efficiently–coupled microring photonic circuit on a chip is integrated with a cold atom system. This platform is fully compatible with laser cooling and trapping atoms, which allows for direct loading of cold atoms in close vicinity of a microring circuit. We discuss our experimental scheme and efforts to prepare for an array of individually trapped atoms within the near field region of a whispering-gallery mode (WGM) in a microring resonator for realizing strong atom–light interactions. Beyond our original motivations in creating an atom-photon quantum interface, we also discuss a novel application – for direct photoassociation (PA) synthesis and quantum state detection of cold diatomic molecules without closed optical transitions. We estimate that the transfer efficiency to a molecular ground state and the subsequent state detection efficiency can approach unity with strong photon–molecule coupling that could be realized in our microring resonator circuit.