A high-q all-fused silica solid-stem wineglass hemispherical resonator formed using micro blow torching and welding

We report a new fabrication technology for making fused silica (FS) wineglass resonators with arbitrarily sized FS solid stems through a simultaneous process of micro blow-torching and microwelding. The process allows the welding of multiple FS structures at controlled locations during blow torching. We demonstrate a new micro FS wineglass resonator with high quality factor (Q) and long ring down time (τ). The resonator is formed by blow torching and flowing a thin FS substrate using vacuum to form the resonator shell, and by welding the shell to a solid post at a controlled location. The flowing of the shell and welding to the rod is performed in one step and in a single mold. This solid-stem resonator offers low anchor loss due to the large stem length/stiffness, and small shell rim thickness. The device has a shell radius/height of ∼2.8 mm, and a stem radius of 0.5 mm. At <10 µTorr vacuum, the n=2 wineglass mode, located at a frequency (f) of 22.6 kHz, has σ = 35.9 s and Q = 2.55 million.