Collective interactions in dense atomic clouds near a micro-ring resonator*

Dense atomic clouds have been trapped and cooled over a micro-ring resonator recently by the Purdue group [1]. The ring resonator acts as a whispering gallery mode cavity that can evanescently couple with the atoms, facilitating chiral collective interactions. We study the interplay between this chiral interaction through the micro-ring and the dipole-dipole interaction through free space, which gives rise to interesting subradiant and superradiant states. We also calculate the changes in experimental markers, such as linewidth and shift in resonance as we increase the atom number and the density of the ensemble. We computationally simulate the system in the low-intensity limit, using both density matrix and mean field methods.

[1] Trapped atoms and superradiance on an integrated nanophotonic microring circuit, X. Zhou, H. Tamura, T.H. Chang, C.L. Hung, arXiv:2312.14318