Packaged Ultra-High-Quality Optical Whispering Gallery Mode Microresonators with Air Tightness and 3-Axis Adjustment

Whispering gallery mode (WGM) microcavity has become an important platform for optical research and application due to its ultra-high quality factor (Q-factor) and low mode volume. However, the surface of crystalline microcavities and fiber-microcavity system is extremely sensitive to environment. The optimal coupling between WGM microcavity and tapered fiber depends heavily on observation of optical microscope and adjustment of precision mechanical instruments. In this paper, we present a novel packaged device for high-quality WGM $\mathbf{MgF}_{2}$ and $\mathbf{SiO}_{2}$ microcavities with 3D adjustment, good portability and high air tightness, which not only ensures the long-term stability of the microcavities' Q-factor, but also realizes the real-time control of fiber-microcavity coupling system. The proposed device has shown great potential for onsite applications outside the laboratory frame.