Effective mechanical trimming of micro shell resonator with T-shape masses

This paper describes a novel method to reduce a frequency mismatch between degenerate modes of micro shell resonators (MSR) with T-shape masses caused by potential fabrication imperfections using femtosecond laser ablation. A systematic trimming process is presented to compensate for frequency mismatch through finite element method (FEM) simulations. A significant reduction (>10×) of the frequency split of the wineglass modes is achieved in the trimming experiments with an imperfect fused silica (FS) MSR using low power femtosecond laser ablation, which further demonstrates the feasibility of the method.