Tunable open-access microcavities for on-chip cavity quantum electrodynamics

We report on the development of on-chip microcavities and show their potential as a platform for cavity quantum electrodynamics experiments. Microcavity arrays were formed by the controlled buckling of SiO2/Ta2O5 Bragg mirrors and exhibit a reflectance-limited finesse of 3500 and mode volumes as small as 35 lambda(3). We show that the cavity resonance can be thermally tuned into alignment with the D2 transition of Rb-87 and outline two methods for providing atom access to the cavity. Owing to their small mode volume and high finesse, these cavities exhibit single-atom cooperativities as high as C-1 = 65. A unique feature of the buckled-dome architecture is that the strongcoupling parameter g(0)/kappa is nearly independent of the cavity size. Furthermore, strong coupling should be achievable with only modest improvements in mirror reflectance, suggesting that these monolithic devices could provide a robust and scalable solution to the engineering of light-matter interfaces.