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摘要
This paper proposes and demonstrates an improved process to fabricate fused silica (FS) microshell structures using a whirling platform and femtosecond laser ablation. The micro-blowtorching process is modeled analytically to analyze the final geometry and thickness of the microshell structure. After the factors that affect frequency symmetry are analyzed, the whirling platform is presented to enhance the structural symmetry in the molding process. Femtosecond laser ablation is used to improve the processing quality in the releasing process. The FS microshell structures are fabricated by the micro-blowtorching process using the whirling platform. The surface roughness is measured with an atomic force microscope (AFM), showing a sub-nanometer smooth surface quality (0.404 nm Ra). A roundness measuring instrument was employed to characterize the geometric parameter error. The 4th harmonic error was effectively suppressed, which contributed to the improvement in the frequency symmetry. The microshell resonator with T-shaped masses was released with femtosecond laser ablation, which revealed good ablation quality on the side wall. The wineglass modes were verified with electrostatic actuation and capacitive detection using out-of-plane electrodes. The experimental results reveal a relatively good frequency symmetry (Delta f(n=2)/f(n=2)) ranging from 0.07%-0.83%. The minimum frequency mismatch was tuned to 0.02 Hz by applying a DC voltage. The maximum measured Q-factor was 95.27 k.
- 出版日期2018-11
- 单位中国人民解放军国防科学技术大学
