Wall-thickness-controlled microbubble fabrication for WGM-based application

We present a wall-thickness-controlled microbubble fabrication model for whispering-gallery-mode (WGM)-based application. The process of fabricating the model is divided into three sequenced steps: geometry size change of the microcapillary during drawing, expanding the process under internal injection air pressure, and microcapillary waist swell into a microbubble. Experiments were carried out to verify the effectiveness of the model. Experiment results show that wall thickness can reach 1.28 µm-1.46 µm at different injection pressure ranges of 50 kPa. The expected wall thickness of the microbubble can be achieved by changing injection pressure while keeping the diameter, which helps to prepare the required microbubble for practical application.