Integration of fiber-coupled high-Q SiNx microdisks with atom chips

Micron scale silicon nitride $\left(\mathrm{Si}{\mathrm{N}}_x\right)$ microdisk optical resonators are demonstrated with $Q=3.6\times {10}^6$ and an effective mode volume of $15{(\lambda ∕n)}^3$ at near-visible wavelengths. A hydrofluoric acid wet etch provides sensitive tuning of the microdisk resonances, and robust mounting of a fiber taper provides efficient fiber optic coupling to the microdisks while allowing unfettered optical access for laser cooling and trapping of atoms. Measurements indicate that cesium adsorption on the $\mathrm{Si}{\mathrm{N}}_x$ surfaces significantly red detunes the microdisk resonances. Parallel integration of multiple (10) microdisks with a single fiber taper is also demonstrated.