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

Micron scale silicon nitride (SiNx) microdisk optical resonators are demonstrated with Q=3.6×10^6 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 SiNx surfaces significantly red detunes the microdisk resonances. Parallel integration of multiple (10) microdisks with a single fiber taper is also demonstrated.