Six million Q factor micro fused silica shell resonator with teeth-like tines released by femtosecond laser-assisted chemical etching

The quality factor (Q factor) is a crucial performance parameter for resonators. In this paper, a novel release method for high-quality micro fused silica shell resonators with teeth-like tines with good surface morphology is proposed. This method is based on femtosecond laser-assisted chemical etching. First, the optimal energy range of femtosecond laser modification is obtained through mechanism analysis. Second, the optimal parameters for a straight line and arc pattern are determined by optimizing the average output power, processing speed, and processing spacing. The results demonstrate why edge breakage in rounded corners is easy under different parameters. Finally, according to these conclusions, the processing is performed on a micro fused silica shell resonator with a Q factor exceeding 6 million. In addition, subsurface damage is rare throughout the fabrication process, and the surface roughness of the released cross section reaches the nanometer level. The improved Q factor helps suppress mechanical thermal noise and reduce zero bias and zero bias drift, constituting the primary method for enhancing the performance of the resonant gyroscope.