Micromachined high-Q fused silica bell resonator with complex profile curvature realized using 3D micro blowtorch molding

We present a high level of control over complex profile curvature in micro fused silica shell resonators achieved through a blowtorch molding process. The graphite mold geometry is imparted on the shell without transferring the texture, preserving the 2.4 Å surface roughness of the reflowed fused silica. A variety of shapes are possible using this technique, including a bell shape with a height-to-radius ratio of 1.2. The shell will gently curve around sharp corners but can also follow a curvature prescribed by a rounded or conical sidewall. We offer an explanation for the mechanism that enables this process. We also discuss simulation results on anchor loss and thermoelastic damping and measure ring-down times of 6.7 seconds at ~12.9 kHz for both n = 2 wineglass modes of a bell resonator.