High Q silica microbubble resonators

Microbubble resonators (MBRs) combine the unique properties of whispering gallery mode resonators with the intrinsic capability of integrated microfluidics. Here an improved fabrication method of MBRs is presented, based on the heating of a slightly pressurized capillary by a rotating arc discharge. Rotation of the electrodes ensures an homogeneous distribution of the heat all over the capillary surface. The demonstrated MBRs have Q factors up to 10 7 at 773 nm. Microbubbles were filled with water and aqueous solutions of ethanol in order to test the refractive index sensing capabilities of such resonators, which also show a good temporal stability.