We demonstrate an efficient optical guiding technique for coupling cold atoms in the near field of a planar nanophotonic circuit, and realize large atom-photon coupling to a whispering-gallery mode in a microring resonator with a single-atom cooperativity C≳8. The guiding potential is created by diffracted light on a nanophotonic waveguide that smoothly connects to a dipole trap in the far field for atom guiding with subwavelength precision. We observe atom-induced transparency for light coupled to a microring, characterize the atom-photon coupling rate, extract guided atom flux, and demonstrate on-chip photon routing by single atoms. Our demonstration promises new applications with cold atoms on a nanophotonic circuit for chiral quantum optics and quantum technologies.
@article{arxiv.2111.01119,
title = {Coupling single atoms to a nanophotonic whispering-gallery-mode resonator via optical guiding},
author = {Xinchao Zhou and Hikaru Tamura and Tzu-Han Chang and Chen-Lung Hung},
journal= {arXiv preprint arXiv:2111.01119},
year = {2023}
}